I'm guessing that you bought your MH from Camping World so suggesting that you go to the dealer where you bought it wouldn't work. Just doing a quick search for RV repair places in your area comes up with several but one of them that stands out is
1st Choice RV .
They're a mobile service so would come to your location to do an install. RVservicereviews.com gives them a good rating. Google reviews are also very good
https://plus.google.com/101280159866166957149/about .
My slide toppers are made by Carefree of Colorado and cost around $1200 and that included installation.