You currently have: Intel P55 Express = Chipset, LGA 1156=CPU socket:, Core i5-560
That is a good MB with OK cpu,
For video you have an AMD HD 5570. That's better than integrated graphics for gaming, but certainly not as strong as your CPU. For gaming your first upgrade should be VIDEO.
This post says you might have a 'Max Wattage' = 450W, 'Peak Wattage' = 500W pwoer supply which is enough for a high end video card.
http://www.thestudentroom.co.uk/showthread.php?t=1612177
This ref will point you to the right video card in your price range. Start with the $110 5770 and then get that or something better. There is no point gettign anything smaller with your current card.
http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-3.html
Good Luck. Post if this is what you needed, or if you really did want a MB swap because something was dead.