What is the most updated logic board I can replace mine with?

Model: 13" MacBook Pro (mid-2009)(MB991LL/A)

Experimentally, I am looking to replace the logic board in my 13" MacBook Pro (mid-2009)(MB991LL/A). I would like to replace it with a more updated logic board that can handle a better CPU. My question is: What is the most updated logic board that will fit inside this MacBook Pro? I could simply purchase another logic board from a 2010 - model, but I want to be sure that the screw set (and screw holes in the logic board) will fit correctly.

Any help and information is greatly appreciated, thanks.