Duo Core E5200 @2.50GHZ , 6G ram , GeForce 9500GT 1024ddr2 , 600 ps , vista 64 . should i upgrade the ps and video card or just get a new pc..? benchmark was like 700 or so
600W PSU should be fine. Video and Processor will both need to be upgraded. Upgrading the processor will typically mean upgrading the motherboard too, possibly RAM. Total cost will be about 500-650ish to upgrade these to something that will result in average performance. More if you want better.
Most retail systems come with video cards that will not play XIV well and if you were to buy a new system plus video upgrade, you're looking at $850-1000ish.
Video: If it doesn't say "GeForce GTX 200/400" or "Radeon 48XX/57XX/58XX/59XX", it will not give anywhere near a decent performance.
CPU: If it's not at least a quad core processor it will not give anywhere near a decent performance.
Read this post
for more specific advice beyond that.
As to whether you would replace your CPU/MB/RAM/GPU for a lower price or whether you'd buy a new one for more money, that's totally up to you. This thread
has advice regarding retail systems and what to look for. (Scroll down near the bottom half of the thread, ignore the top half; those are all bad systems).