Buy decent wheels.
Ride bike.
When you feel like a better bike, buy a better frame, your wheels will probably still be in good nick (they last a long time if looked after).

Of course, there's nothing wrong with eventually buying a decent bike and keeping the old girl for trips where you don't want to risk the good bike.

One thing's for sure, if the bike doesn't ride well, you won't enjoy it and you won't ride it. Wheels are a major part of that. They don't have to be expensive wheels, just decent and you've had some good guidance on where to go there.