Keep my Q6600... but what about graphic card?

I've read a lot about "you have to upgrade because..." and all sort of things, in my exp i keep my Q6600 cuase it capacity to OC at high clockrates with less money:D and its a quad, but what do you thing about upgrading my Radeon HD3560 to a HD4670... or even a HD5670???...im really thinking about it, im from colombia so my budget is VERY limited... but ai have things to sell to help me out with... gime your best shots

my rigg:

Intel Q6600 @ 2.4Ghz (for the moment hehehe)

3Gb DDR2 SDRAM @ 800Mhz

Radeon HD3650 256Mb DDR2

rest of the parts come with my DELL VOSTRO 420 parts... so every thing is DELL from the mobo to the case

if you have any suggestions about the "vostro rigg" please tell me... mobo and everything

You would need a new PSU to upgrade the GPU significantly. I suggest you get a new PSU then save up and get a 4850Duckman5

this is probably for the best. or grab a 9800gt instead but yeah new psu required.

there is absolutely no need to upgrade a Q6600 right now. it's overkill for any game. your graphics card sucks bad. that's your pc's weakness. get a gtx 260 or radeon 4870rock_solid

You would need a new PSU to upgrade the GPU significantly. I suggest you get a new PSU then save up and get a 4850Duckman5

see... i have a 600w PSU, upgraded it few months ago... i'd like a DX11 card (for future games) but its not a REAL 600W PSU... like the HD5670 cause the budget price but i dont want to change the graphics card at least for a year or 2... keep suggesting please

btw, exist some way to get Crossfire or SLi without 6-pin connector or even with my PSU?