There's room for over clocking the 6300 mate but its imperative you get a flat downward blowing aftermarket cooler that gives secondary vrm cooling.
That board is very very similar to the the 6300 rig in my SIG below - 4.2/4.3 is not a problem so long as you cool those vrm's as well as the CPU.
Are there any online shops you can use so I can see whats available in in your area??