To be clear this series came in four configs an i5 2.3GHz and a i7 2.5GHz either with 8 or 16GB of RAM.
So yes, you could swap out the i5 with the i7 board [product|IF123-216-2] but given the cost & limited performance improvement, I don't think it's worth the effort.
You might want to look at the newer M series 13" MacBook Pro as a better investment and gain a lot more performance!