My Maibock went sour...next step?

So the Maibock i've been lagering got infected. Probably because my femerntation took forever (over a month) and totwards the end I was checking the gravity every other day. I've tasted it, and while it tastes good it's definitely a little sour. What should I do? If I bottle it now will the "souring" process stop? I don't want it getting anymore tart. It's actually quite refreshing as it is right now. Never had a sour lager before

Metabisulfate will probably kill the infection. I don't know of any brewers using it, but that's exactly what winemakers us it for, so it's worth a shot. At beer pH I think 100ppm would be sufficient.