If you have the frame work, you need to determine what brand and model you have. Most of them work pretty much the same. Two of the most popular are A&E and Carefree.
is a link to the A&E 8500 and 8000 series. For other models just use Google and search fro something like "A&E 9000 awning manual".
The fabric or canopy is replaceable, but you have to be very careful due to the tension springs in the awning roller tube. Most of the parts are readily available from most RV stores. Try PPL Motorhomes in Houston or RV Upgrades (a site sponsor).
Sounds like you got a typical RV sales person. He was probably selling used Yugos last week. I'd go back and discuss the awning wit the service department and bypass the salesman.
Sounds like this is your first RV. I would find an independent RV technician to check the RV independently of the dealler. It will run $200 to $300 but well worth the peace of mind. Also have the dealer do a PDI and fully demonstrate all of the systems on the coach prior to signing the papers. Also have the dealer provide a full chassis service on th ecoach...oil and filter change on the engine and generator, transmission oil change and lube the chassis. If the tires are over 5 years old, I'd have them replaced as part of the deal of drop the price to cover a new set of tires. The tires have a date code stamped on them that shows the week of the year and the year manufactured.
DO not get caught up in the heat of the moment and just look at the pretty part, look at the mechanical part as well. Check www.nadaguides.com
for pricing. In the current market, RVs are selling for less than low retail without option add ons.