I would just put it on a disk. I am in the same situation but with a little more space needed. You can pay monthly with those companies listed above, but with my budget it wouldn't work out.
Go with USB 3.0. Even though if your computer still has a 2.0 still, get the 3.0. I would also recommend the Sandisk Extreme model. Kingston also has a lot of good reviews. You might as well go with a 64GB since it does not cost that much more.
Found this article which compares USB flash...
Did you assign the drive?
http://answers.microsoft.com/en-us/windows/forum/windows_7-hardware/lacie-hard-drive-not-recognized-by-windows-7/98ad2be5-b8cf-4cca-9c9c-aef0c57ab531