You can keep the standard front sight. If you scope your rifle you won't see it.
I like GG&G products. They make several mounts for railed forends that should suffice. I've used YHM, GG&G, and ARMS BUIS. If I had to pick I'd go with the GG&G A2 flip rear sight...the ARMS folded has a lower profile, but the GG&G unit feels more substantial (i.e. tougher)(just my $.02).
As I mentioned earlier, you probably ought to buy a railed forend considering the number of additions you want to make. YHM is good for the money, but LaRue and Daniel Defense are some of the best. B/C you just purchased your rifle I'm assuming that money may be a little tight...if so, go with one of the YHM units...I don't think you'll be dissapointed...not to mention that there are a couple members selling combo units (forend, flip front sight, sling attachment) for around $185.
Scroll through the EE to get a feel for the going rates before you buy...check the feedback forum before you buy. Most of the guys on this board strive to be honest and you should have pretty good luck.