Detailed trigger hone info can be found in the FAQs, hundreds of first timers here have done their own trigger work, the hardest part is building up the confidence to just do it, it's not all that hard if you know you can use hand tools, just go slow and easy on the honing and test often so you don't go too far and make the trigger too light and unsafe.
Parts can be ordered from Numrich, so even if you do, all is not lost. You also have the option of sending it to H&R for a trigger job, that info can be found in the FAQs also, they may or may not charge for it, depends on how heavy the trigger is.
Tim