Answers

If actual damage has occurred to the roof, due to hail, there is really no other way to fix the damage, except replacing the roof system.  

Depending on the type of roof that you have, if the damage is minor, you might be able to complete a spot repair, but that also depends on the condition of the roof.  Hail typically falls randomly over the entire roof, so when there is damage, it tends to be all over.  If your roof is older, it might not be in repairable condition, or your roofing material might have been discontinued and have no match available for sale.

I suggest having a Haag Engineering certified roof inspector or a structural engineer evaluate the roof and tell you if you have another option.  

Call a professional certified roofer who can do a full inspection and report of how to proceed. Professional roofers can bring insite and cost savings others might not. They have years of experience and a trained eye to make sure all problems with a roof are discovered and remedied! Remember - When hail hits an asphalt shingle it often knocks off the protective granule coating. Once the granules are gone, the protective layer underneath is exposed to the elements. Always call a professional roofer!