"We come to you in November."
Translation:Vi kommer till er i november.
Those aren't prepositions, they're pronouns - and while English uses "you" for both, if you change it to third person, it's easier to see the difference:
du is to dig as "she" is to "her"
So since you say "we come to her", it's vi kommer till dig. (Note that it's not komm.)
The same goes for ni and er.