To me it sounds like you have 2 options.....
---find the time to convert your shed...
----or, open your wallet.
Now, there is a chance to MAYBE find one on craigslist, or at least the supplies to build one from there. Ask around in the feed mills and see if someones taking down some outbuildings... if you help, or will at least clean it up, they will usually give you the things you need. The good news is, with a secure coop and run, roost for their fluffy butts, a nest box or 5... (you are going to have quite a few birds), food and water.... you WILL have the summer to complete the shed. Winter is a while away, and as long as they are secure... time to complete will be probable.