The 737-200's will be leaving soon. Then the 737-300's. Renovations are a waste of money, most 737 flights are on less important markets. The 757's will probably be gone in a few years.
The 737's will be replaced with a combination of CRJ900's and A319's. No plans for the 318's as far as I know. The 757's will go A321's.
The fleet will be 319/320/321... great for the airline, single pilot scheduling/pay/type ratings.
-Sean