New computer or new hardware, please help?

You should just buy a whole new system. The 3800+ is a dinosaur at this point. Also to do video editing you would need about 6 gigs minimum and a at least a quad core processor to be productive. Also a good video card would also help out. AMD has a 6 core processor's called the phenom II 1055, 1075, 1090T and they also have an 1100t all of which are very fast for video editing. Intel has even faster CPU's called core I7 2600k which cost more but they are over all faster.