As a fellow student who understands what you are going through, let me give you a few pointers. I have never had a problem finding employment, and have received every job I went out for. I have found that the interview process is the most important thing out there. I have a lot of friends who went to Caltech, as you know that is an extremely good school with extremely high caliber students, yet many of those students find themselves unemployed, and unemployable. This is because they have very weak social skills, along with a very timid personality that makes it impossible for them to convey their capability to their prospective employer.
Interview skills are KEY!!!
First, you need to understand that this interview process is a two way street. If you are interviewing for a job, it is because they need someone to fill a position just as badly as you want to fill it, and you would not have been asked in if they did not already think you had the basic skills to perform the job. Everyone that interviews for that position will have roughly the same abilities, so it all comes down to the personal interaction.
Before going to the interview, research the company you are interviewing for. Find out what products they are creating, what they have already done, what they plan or want to branch out into. Then do other research on various technologies that apply in some way to those products. It is optimal to know exactly what project you will be working on, but if not, you should still have a general idea as to what they produce. Write down a bunch of questions, and try to answer them. You should have at least 5 questions that you cannot answer, and will need to ask your interviewer. This will show your prospective employer that you care enough for the company to have researched them, and that you are actively interested in the job.
My father is an engineer and he would rather hire someone out of school with a 3.0 who genuinely is excited about their projects than a 4.0 who is just looking for a job.
Mindset is VERY important. Absolutely walk into the interview KNOWING that you are NOT going in as a desperate supplicant, but as a qualified skilled worker with something THEY NEED to have. Keep your head held high, maintain eye contact with everyone you meet. Sometimes employers will ask the people you met prior to and after the interview what their gut reaction was to you, you want them to remember you as confident and cordial. Even if you are new to the field, sometimes especially if you are new, this attitude is necessary. They know what your level is, but if you are there, they want you anyway, so don't worry about your lack of experience. Some employers find this preferable, that way they can train you to their way of doing things without having to train out "bad" habits from a previous job.
Walk in dressed and propped appropriately for the occasion. I interviewed for an intership at the Salk Institute, which is a very prestigious research institute, so I dressed in a conservative suit, and brought a professional black leather folder that held a classy Cross pen, a nice pad of paper, copies of my resume and references printed on good quality paper, and a list of printed questions to ask my interviewer. I was a sophmore in college, barely getting into Biochemistry, but I walked in and told them in no uncertain terms that I was a hard worker who loved this field, was excited about its prospects, related some ideas that I had and wanted to try out, and let them know that whatever I didn't know, I would be more than happy to learn whatever was necessary to get the job done. They offered me the job right there and then.
On the other hand, when I went to a job interview at JPL, I learned that the climate was much more casual, so I wore a nice sweater, a good pair of jeans, and a nice pair of shoes. I brought my leather folder, but I replaced the Cross pen with a mechanical pencil, and of course the resume, references, questions and research, and awesome, self-esteem filled attitude. I had a wonderful time working for them, it was by far the most wonderful experience of my life. I still do some side work for them when I have the time, I'm currently recovering from a back injury, but will be back to work soon.
Ultimately, it's all about attitude. Remember......they need you as much as you need them, perhaps more. Let them know that you really want to get back to school and get a BS, they like to hear that you have higher aspirations then being a tech.
Good luck, and if you would like, I'd be more than happy to help you get through this situation, just throw me a line!