CrossRoads:
I was going to suggest adding a FRAM memory chip, fast access like serial SRAM but with EEPROM nonvolatility - thru hole parts have become ridicuously expensive.
Small SMD part with a few k bytes to hold lots of info would be very little, just $1.40 for a 5V part. Pick up a DIP adapter from proto-advantage.com for easy breadboarding.
http://www.mouser.com/Semiconductors/Memory/F-RAM/_/N-488wv?Keyword=fram+memory&FS=True&Ns=Pricing|0
FM24C04 - 4Kb FRAM Serial Memory4K-bit (512 bytes) through-hole are available on eBay for a pretty reasonable cost
I see two candidates...
Qty 5, $8.99
Qty 10, $13.99
Both from China, free shipping.