When you say it has a mount just isn't enough to go on. There are dozens of "mounts" out there. Some are fairly generic, some are proprietary, from the awning
makers. A picture of your mounts would help.
If you are talking about one of those continuous extruded channel rails, then that would be a Keder rail. It will accept either a bag awning, which I find to be heavier, more awkward to store and deal with, or just a simple "Rope & Pole" style awning that just slides in and out of the track in the channel. I much prefer the latter, as I can remove it, stuff it in its storage sack, and stow it just about anywhere.
Here's a couple of pics of mine, and if this is what you have, then I would recommend Marti's Awnings. Very good quality and quite reasonably priced. Awnings are all she does, and they're done right. You can order any number of styles, colors, and she will custom size it to whatever dimensions you want.
Marti's Vintage Trailer Awnings