Depends on what photos you took, though. If you can get very close, then get a good wide angle lens. If you can't get close, then tele. If they hired you, you can probably be close enough for just a good 17-50mm for now. But of course, if they like your work so much that they hired you, you must be doing something right
And yes, don't worry too much about IQ. With political campaign photos nobody expects studio quality. What is more important is that you get photos of all the important rituals, handshakes, the important people. And good angles, to make the politician look good and confident, make the room look full of supporters.