My wife and I after doing a ton of research finally found a kennel that we decided to buy from. We found the name of the kennel here on Leerburg and fell in love with his program for GSD's. We went to the airport and picked him up last Friday and have been playing with him and cleening up after him ever since.
Yesterday Cody had his first visit to the vet and after telling us that we had a very smart, calm, and a little over weight puppy that he also had a "gallop" in his heart on the left side. Of course we were very worried but he assured us that this somtimes happens and the go's away after the puppy reaches 3 or 4 months. Now regardless of what happens we have already decided to keep Cody, but should we be worried? Should we limit his play, or walks? My vet really did not seem concerned and said that he didn't want to mark it in his records yet but that he would monitor his progress. My wife and I have never had anything like this occour befor and are obviously worried, if anyone has experience with this please let me know.

DISCLAIMER: I am not a Veterinary Medical Expert of any sort!

I wouldn't be too worried (based on the Vet's statements), but I would have him checked monthly to track his heart's progress.

As for as activity goes, let him be your guide.
It is normal to rest after exercise, but if he seems overly sleepy, it was probably too much.

How old is the dog?

I would also add that I would be in contact with the breeder about the issue.

I'll assume that a "gallop" is the same as a heart murmur?

I was assuming sinus arrhythmia.

Sorry let me add that this is a heart murmur and that it is on the left side only not the right. Also my puppy is 8 weeks going on 9 and that we have another apt scheduled in 3 weeks.
I wasn't sure wether to contact the breeder or not becaus although I do have a health guartantee I don't want another puppy.

You absolutely should tell the breeder. Any breeder worth his or her salt, will be wanting to keep track of ANY health problems in his/her dogs' bloodlines. This will affect future breeding decisions. It does NOT mean they will take your puppy away from you!