Replacing sofa air mattress - Bighorn

We have a 2008 Bighorn 3670RL and have discovered a small hole in the sofa air mattress. Do I have to get a replacement air mattress from a RV dealer site or can I purchase one from a store like Bed Bath and Beyond? Just by guessing I think it is a full size mattress - I will check before buying! Thanks, Chris

Both bighorns I have owned came with a repair kit under the couch in the drawer. If it really is small it should be repairable.