Hardware updating..

[Exploration]

Alrighty so i have some cash laying around and seeing as how i've been neglecting my PC by spending it all on the car, i decided it's time to update this thing a bit.

Currently it has an Asus mobo with an Intel 1155 socket. On said socket is an Intel i3 3240 @3.4Ghz. I'm not noticing any performance problems but this CPU has done a fair amount of work in the time i've had it (Nearly 3 years) and i bought the thing second hand from Ebay for £35. Which back then was a steal for the performance it dishes out. However it is getting kinda old now and i'd like to replace it with something more powerful and hopefully future proof this thing for a couple years.

I was considering replacing the whole board with an AMD setup. However i'd prefer to not replace my RAM as that's just more expenses and i really don't want to then let this thing turn into a money pit. The other factor is i know absolutely nothing about AMD. I've spent years using Intel/Nvidia combinations, so my knowledge ends there. My PC currently runs 8GB of RAM DDR-3 at (I think) 3400 Mhz, i could be wrong about the clock, been a while since i looked at the spec of my own PC seeing as how it's handled things flawlessly since it was built. But i'm certain about the type.

The main reason for this idea was i'm planning on getting Arma 3, the new Tomb Raider etc. I'm pretty certain my EVGA-Nvidia 750Ti FTW Edition will deal with these games to my satisfaction so i'm not looking to replace the card, as honestly, as long it gets more than 38FPS on high-V High settings i'm happy. (There's still a decent headroom for overlocking it by another 300 Mhz core and 150-200Mhz Memory. At least thats as far as i got it on the test with my i3) But the CPU i feel is going to seriously struggle with Arma and Tomb Raider. It's managed to handle games designed for quad core machines but i honestly think it's going to be out of it's depth now. So along with this does a Nvidia card work with an AMD based board? i honestly have no idea and i know it seems like a noobish question.

Cheers for any input folks as always!