With the DAG ever increasing, hashing/mining Ether will mean your 3GB GPU's or lower won't work anymore.
You can either mine another coin like zcash or monero, or upgrade your cards. I'd go for the former :-)
Zcash and monero are slowly gaining ground and it's almost certain that they will hit a point where it climbs exponentially, so you may as well start now and hold on to those coins you mine for a big pay out in the future.
Use an app like NiceHash Miner to mine the most profitable coin at the time, and it even gives you a breakdown of how much you're much money you're making each day.
I'll be adding new posts regarding the DAG and general mining stuff in general, so please give me a follow to stay up to date :-)