Macbook failure

My Macbook (13″, purchased May ’07) just ceased to boot (black screen on startup).  Tried all the standard tricks, no luck.  Took it in to the Apple store and they tested and declared that one of the memory (RAM) slots had failed, but it would boot if I removed the RAM from that slot.  They said the flat rate for repair (regardless of problem) is $280.  I’m opting to replace the RAM in the remaining slot with a new stick that has twice the capacity (1x1GB vs. 2x512MB) instead, sacrificing half my RAM bandwidth for $250 (the RAM cost $30).  New Macbook soon?