Memmory Data (RAM)is not affected by reset , if you are having problems with the data being reseted to 0 or other values , then there is some code that loads something into your variable. i don't have experience with C programming , but there should be some other ways to tell the compiler not to initialize the Variables defined . you have to state what C compiler you are using to make someone able to help throught.
And if you do want your variable to be saved ,even in case of lost of power you'll have to use EEPROMs. if you want an integrated EEPROM you can use atmel AT89S8252 or newer one the AT89S8253 ,which has 2KB of EEPROM.

Farshid