I am afraid that I am taking my pup for too long of a walk. I take for about 5 minutes in the morning and then in the afternoon I take him to the park which is about a 5 minute walk but sometimes I spend about an hour up there, but we sit down for most of it, then walk back. Is this too much? My pup is 13 weeks old.
Thanks in advance!

It doesn't sound like you are overdoing it.  As long as the pup isn't showing signs of being overtired, it sounds about right.  No longer then that for a while though.

An hours sit in the park watching the world go by will be great training for him.

My pups 13 weeks too and i recently just took him to a show and he laid down on the grass most of the time, occasionally sitting upright to bark at passing dogs! :D He loved it, great socialisation!