I totally agree with Steve on that one. The best way is to set up a trace. About the information about the last six months, I don't think there is a way of getting this information either.

Maybe something that could be interesting for you is the "Enable Trace" option. It by default is set up to obtain DDL statements but you could add some specific events, like sp's execution.

The catch with this option is that you would have to see if you suffer any performance issues. It's not supposed to be as heavy as profiler, it's actually supposed to be a lot lighter but you would have to try it out.

Hope it helped in any way.