Then the OP is in luck - the second code set listed here
http://www.picbasic.co.uk/forum/showthread.php?t=2129
maintains time as well as most RTC ICs and could easily be ported to 628A or similar. This code is around 30 lines or so of instructions to do this.

Also, if the OP only wants 10 minute intervals over 48 hours, the 628A could be used without external EEPROM ... stash some in the on-board EEPROM and the others in DATA MEMORY. It's battery powered - just do not turn it off until the data is downloaded. This could be a stepping stone to more data and and external EEPROM.

The manual has the "RS232" connection for PIC direct to PC - see SEROUT for example. No need to add MAX232 unless he want to do it really right. Again, a stepping stone to more complexity.

Just some ideas - good luck blinking your led.