A quick search reveals a number of Optio 330 owners searching for a USB driver that works with Windows 7 both 32 bit and 64 bit. It does not seem to exist and the only solution offered is to buy a card reader. The camera is over 10 years old and if it were me I would retire it and get something a little more modern. But if you want to keep it then a card reader is the only answer.
Here is a link to one that costs less than $7. I am not recommending it, just an example, and you really should get one that covers all types of cards not just CF but you noted you did not want to spend a lot, so here is the cheap solution. Just do a search for "Compact Flash USB reader".