First off, what don't you like about your current bike? And next, are there any things that need to be replaced (eg. things that are broken or worn, things you just can't stand about your bike, etc.)? Also, do you see yourself getting a newer road bike at some point? After answering those questions I'd then talk to a trustworthy shop.
What's on your current bike? The original components or has anything been replaced or upgraded?
$900 today would buy a very intro level road bike. Closer to $1,500 will get you a nice road bike with mid-level components (with Shimano, think 105). It makes more sense financially in a situation such as this to go for a newer bike (unless you absolutely love your current frameset, it fits your needs as well as your body, and you don't see yourself buying a new bike, etc.) as bike manufactures are able to get the components for so much less, so it's a better bang for the buck.
A bike shop will make more money fixing up a bike than if one were to buy a new bike (unless of course, the bike to be purchased is a very expensive one) so do keep that in mind. In some cases it certainly makes sense to fix up a bike rather than to buy a new one, but in other cases, it's sometimes best to buy something newer.
If you think buying a new bike may be the best thing for you, I'd do what absolutely had to be done to your current rig (saddle included as that could be very easily moved to another bike) and save up a little more cash in order to get a bike with mid-range components vs. low-range (it's definitely worth it!).
Hope this isn't too much information!
Last edited by LivetoRide; 03-23-2011 at 04:53 PM.
"Limits are a state of mind: break them before they break you."
--Michael Cotty