[clyde]

I don't know where you are related to downtown Boston, but the first O'reilly I checked in Everett shows 5qt Mobil 1 EP 5w-20 as in stock for $38.99.

Given your use case of not many miles and not severe duty, I'd get a jug of that and be done until next year. The one quart of 5w30 in the mix for that little use isn't going to matter.

I also wouldn't worry too much about finishing with what you have on hand and, at most, plan on changing the oil a little earlier next time.