How hard is it to repair a leaking roof?

We have a manufactured home, but it has a shingled roof. We have a bad leak somewhere (it puddled on the roof inside, so now we have a water stain and bowed roof in one spot.) :(

Would this be very difficult to repair ourselves? My husband is very handy, but has never done any roof work.

I'm just worried that we won't be able to afford the repairs.

Thanks!
we don't even have an attic. :( It would be a crawl space for the inside between the ceiling and the actual roof.

View this post on my blog: http://madeinhome.info/how-hard-is-it-to-repair-a-leaking-roof-2