Your choices are limited here.
If you had a 2.3GHZ system you could swap-out the logic board with a 2.7GHz board. Otherwise you have no upgrade path staying within the same generation.
In any case you can't swap-out the CPU by its' self (soldered on) and you can't swap-out the logic board for a different board than what the system was intended to have.
With that said, you might be able to swap it out with a MBP "13 '12 non-retina version. I would strongly recommend you double check with the supplier if it's compatible and can return it if it doesn't work. I've not tried this, but the systems are very similar so it might work. Good Luck!