Take a good look at the dish and carefully move it a bit up and down and then side to side. Try to determine which one of those two directions it moved. If the foot on the mast isn't fully supported, meaning a bolt in all four corners, than up-and-down movement is very possible. If the foot is solid, the dish more likely moved side-to-side, which is even easier to fix.
Your dish points between two satellites at 110 and 119 West Longitude. You could probably look up the rough elevation and azimuth settings for your dish based on your zip code. But, most likely, your dish moved side-to-side, and by using the signal meters on the receiver, you should be able to realign it pretty easily. You'll need one person inside to watch the meter and one outside moving the dish. The bolts on the dish are all 7/16" heads/nuts, so all you need tool-wise is a 7/16 combination wrench.
Make sure you balance the signal between the 110 and 119 sats; if 119 is stronger, the dish needs to point more east (left, if you're standing behind it), and if 110 is stronger, it needs to point further west (right). Once you get it even on both sats, lock down the dish so it can't turn side-to-side anymore. You can then loosen the elevation bolts and adjust the dish up and down slightly if your signal is still low.
Do NOT attempt to adjust the "tilt" or "skew" (i.e. rotation) of the dish, as it won't have changed significantly.
There are only four reasons your dish could move like it did:
1. The dish bolts weren't tightened down properly. As hard as it is to believe, I see this a lot in the field. It seems a lot of installers forget to lock everything down tight.
2. The dish is mounted on a facia board with the bottom of the foot hanging off. This is very common, as techs are pressured to get systems installed, but many customers refuse to pay for custom mounts that would solve this problem correctly, so the foot is mounted to the facia with only the top half of the foot supported. Strong winds will bend the foot and the dish will move.
3. The dish is mounted to an unsuitable structure. I've seen people put a 4x4 into the ground and mount their dish on it. The 4x4 twists from season to season, and they're always having to adjust the dish. If it's wood, it needs to be supported well enouh that it won't be allowed to bend and twist, or you'll have constant problems. A proper ground mount uses a metal pole set in cement.
4. Extreme weather. Even the best system isn't really designed to deal with 90+ MPH winds and other extreme weather. A few custom modifications/reinforcements or a relocation of the dish can fix those problems, but such would be considered custom work by an installation company.
-Troy