Welcome to GBO! As was said, there's no aftemarket barrel source, if you're not dead set on the 7-30, just get a 7mm-08 Handi, they're great shooters and real popular in a Handi. A rechambered/rebored .223 barrel will set you back about $250-$300, plus the cost of the rifle, a 7mm-08 will cost ~$225.
If you're interested in the stubbing that Larry mentioned, see his "30 Carbine Project" down the page, a very good read and well documented with pics.

Trigger work isn't hard with just a few basic tools, you can find that info in the FAQs and Help sticky if you haven't already, or as Larry said, H&R will do a free trigger job if the pull is over 5lbs, they'll charge for it if it's less than 5lbs already. Best time to get that done is when a frame is sent in for an accessory barrel, otherwise, I'd just do it myself, they're not that hard, many, many folks here have done their own for the first time.
Tim