Hostas don't need a lot of attention, but you may have to re-pot it if it gets too big for the pot it's in at the moment. You can give it a bit of general fertiliser, as it will use up any goodness in the soil very quickly, but I've found that keeping them in pots keeps the slugs at bay. You can always put a few of the little blue pellets in the top of the pot, just in case you get a very adventurous one!!
If the roots are congested and you do need to re-pot, just tip the whole thing out, and cut up the root ball with a spade--you can be really brutal here! Then re-pot each bit separately. Depending on the size of it, you may get 2 or 3 new plants out of it. Good luck! Annie (Cumbria)

Thanks for the info Annie.