What you might want to try, is to take some of the stuff you have improvised, edit it down, write an intro, an ending, a bridge, a solo section, whatever, but take the bare bones of the improv, and build a song out of it, practice that, work out the kinks and bumps and then record it. Improvising is great fun, but it's a lot more fun to do, than to listen too. I don't know what kind of goals you and your band have, but building a repertoire of your own material is usaully high on the list. Also once you write out a tune, you can always stretch it out anytime you want, Whatever you do, enjoy it.....