CPU's Compatible with a DELL XPS 410

I've had my XPS 410 about 2 years. Lately while playing WoTLK my FPS has been dipping really low. Figured a new Video Card will solve the problem. So I picked up a GeForce 9500GT. Has helped but I am still having the FPS dipping down on me. Everyone says a CPU switch should help resolve it.

I'm not looking to overhaul my system or purchase a new one at this moment. (When I do it will be a custom.) It's a pain enough trying to find compatible upgrades for my system. So wondering if anyone knows a compatile CPU that would be a nice upgrade and hopefully combined with the new card will hold me over for another year before I build my new PC?

Also will switching my RAM help at all?

My current system:

GeForce 9500 GT 1GB DDR2

1GB RAM PC2-5300 DDR2 (667 Mhz)x4 for a total of 4GB

Dell Inc. 0CT017 Motherboard, Intel P965/G965 Chipset

Intel Core 2 Duo E6420 (2.13 GHz) Processor

375W Power Supply

your rams perfectly fine.

So I guess I should exchange my card for a different one?

I was under the impression the 9500 was a fairly good card.

Dell will that card work with my system? Also how can I check the PLL chip to see if I could overclock it a bit?

Do you also know a PCU upgrade that would be compatible with my system? I'm looking to upgrade my 410 to the point I can play without my FPS bottoming out in graphic intensive fights and it's so hard to upgrade having a DELL since you can't go and just throw anything into it.

If I went with a Q6600 what else might I need to change? Don't want to overhaul the whole system.

Cool. I have the latest BIOS. Going to try and see if I like the overclock and how it performs. If not may go with a Q6600.

Thanks for the help.