MT-51 Interstate. Little extra cranking amps and it'll drop right in. Probably after this cold snap you'll be good until next year anyway though.
I will be replacing ours come fall, will be four years old, if you make 5, you are lucky.
Looking at an AC Delco for it.
I second this. I used to sell a lot of batteries in our body shop, and I put an MT-51 in my GC, and it fits perfectly.
Look up the Interstate dealers in your area, and call them. Most of the time they are installing it, so the price they sell them for, includes enough profit to also cover the labor. Ask for a cash and carry price, so they can knock the labor off. You should be able to get one at or under $80.
MT-51 is a common Honda battery, so a good stocking dealer will have one on the shelf.