t420 time to upgrade?

Recently upgraded my t420 i5-2520M with 6GB RAM to an i7-2720QM and 8GB RAM. Seems to run a bit hotter and no noticeable processing increase, the only thing I really notice is battery life is much shorter and I can't use my 65W charger while it's on... (only the 90W charger, I'm assuming because of the tdp 35W->45W).

Is it time for me to buy a new computer and if so what or does anyone have any recommendations for upgrades they would perform? I'm tempted to replace the i5-2520M and buy a SSD.