Time for a desktop upgrade. Please help.

[DeadandBuried]

Well in my opinion, You can try buy 2nd hand DDR2 rams to at least 8GB if you doing light videos. that should be enough to help a lot since video editing does a lot of rendering. (8GB for light, 16GB for heavy usage). Your current comp should be ok. You just need the ram as 64-bit in my opinion, needs 8GB for a decent experience.

I felt a lot of difference when I upgraded from 4GB to 8GB.

Let me chip in to say that 4GB to 8GB of RAM does make a difference so I will highly recommend that you do this.

My experience is with Mass Effect 2; it takes a few seconds to load up with 4GB, but with 8GB it went noticably faster. (this was with a Core2Duo and DDR2.) Now I changed to Haswell and 16GB DDR3; it's almost instantaneous!