Well, you might be able to find a chip to go into it on ebay, but I seriously doubt you'll find anything new available. Any further upgrades would probably be a waste of money, and you should save for a full rebuild, however long that may take. Spending on upgrading that would just stall your ability to save to replace the whole thing. Also, if you're focused on saving for that rebuild or new system, you're more likely to save more money and get better returns in the long run. That's my advice, take it or leave it.