There is nothing like a boxer "get together", my boxer Cooper has boxer friends over for play dates. The two that come over are brothers and the three of them run (and run and run and run) and play so well together, which gives them all the exercise boxers thrive on. We have two dogs (one is a lab) the lab can't keep up with the boxer's energy and tires first 100% of the time. The boxer has gotten my lab down to a respectable weight (he lost about 15 lbs after we adopted the boxer) so its been a win win situation for them both.
I am no expert, but I would first let your dog get used to the new environment and then try to find a good match (personality wise) to adopt. My boxer was the second adult dog I've adopted and he is the most loving, loyal pup ever! However, it literally took 2 full weeks before my lab and him played (or even got near one another). They went out at different times and in the house one was crated while the other could safely approach and they could sniff one another. I may have been over cautious due to the fact that initially appeared they would tear one another apart. After two weeks they became the best of friends and now I only need to separate them when they won't quit playing and knocking over furniture (boxer is 65 lbs and the lab is 90 lbs, both nuet. males).
And now that we see they get along so well...we are taking the daring step of introducing a two-legged baby this June. Until the baby arrives these boys have been our spoiled "children" and it will be interesting to see how they respond to the newest addition.
Good luck to you with your new home and possilbe new addition.