Well, if you haven't already done so, CALL THE CAMPUS AND LOCAL POLICE DEPARTMENTS!!! File reports on your laptop. You should be able to call Dell and get the serial number. Check the local newspapers, pawn shops, and eBay auctions. Ask your friends to keep an eye out for it. Regarding the home owner's insurance... it just depends on what company your parents go through. My stuff in the dorm was covered under my parent's policy. If your insurance covers it, they will either give you full or replacement value, depending on the policy, minus the deductable, which is probably $250 to $500. Keep an eye out on the HD forums, and get a new laptop or desktop when a deal comes across. Laptops are nice since they are portable, but they are extremely easy to walk away with, which makes them such attractive targets.
In the future, here are some security tips...
1) NEVER leave your room unlocked w/o someone in it. It only takes a minute to grab a laptop off someone's desk, be out of the room, and down a set of stairs. People on your floor likely won't see a thing, or if they do, won't confront the person. I could walk into some of the dorms I used to live in, walk down the hall looking for unlocked, empty rooms, and be back outside in my car with a laptop in no more than 5 minutes. You may think "I'll only be gone 5 or 10 minutes doing laundry or getting a snack", but it only takes a minute.
2) Consider buying a desktop instead of a laptop. Thieves avoid desktops because they are much harder to make off with, and much less valuable than a laptop. People notice when a person is carrying a computer tower down the hall.
3) IInstall recovery software on the computer. If the computer is put on-line again, it will help find it.
4) Consider getting a lock such that you could cable your computer to your desk.
5) If you get a laptop with a plastic case, consider taking it to an engraver to put your personal information on the bottom. They can actually melt your information into the case.
Good luck.
Ryan