eighty bazillion dollars.

for what's good components: search. for what they'll cost: ebay, google, etc. price things out on your own.

really, it depends on how much your cheap bike teaches you about what kind of ride qualities you're looking for, and there's no right or wrong answer to how much a quality bike will cost. Top of the line everything can easily shoot a future build well over $1000, however most people don't need, or even want top of the line everything for their bike. figure out what components matter to you, about how much you're willing to spend for nice this vs average that, etc etc.

if you don't learn too much from your current bike, drop $300-400 at bikes direct, assemble it properly, and continue riding until you do figure out what you truly want.

if you learn a lot, your best bet might be to build up a frame from scratch, and you can get everything how you like it. (But only if you learn a lot, and really know what you're looking for. It will be more expensive than buying complete, and it will take longer) In general, it seems that many of the nicer bikes come as only a frame/fork/(maybe a headset) combo, anyway...