IRL top quality players can play well into their mid 30s, but in FM once a player hits 30 their technical and physical attributes start declining like no tommorow, so how do i extend or maintain a players attributes so they can play top level football to around 33-34?

You can't. It's one of those things that people ahve been complaining about with FM 2008 in particular in the hope that it might be addressed in the 8.0.2 patch.