I would install Windows 7 32bit rather than the 64 bit version with that amount of Ram.
Reasons are, drivers and general compatibility is better on 32 bit than 64 bit which can be a bit of a pain sometimes. Windows 64 bit uses more memory and 64 bit programs use more memory (about 20%) and 3gb is not a lot of memory.
64 bit windows runs faster, but not if it is swapping out to the swap file all of the time.
Also your hard drive is a bit small for 64bit windows which uses more hard disk space.