I just bring my dog to work with me
. But I know that isn't an option for everyone.
You could try looking under "dog walking services" in the yellow pages or on Craigslist; maybe try calling some local dog schools for recommendations. I bet you could find someone to come take the puppy for a walk mid-day, and since you are only gone all day three days a week, it shouldn't be too expensive.
Doggy Daycares are great for some dogs, but not all. And there are some really, really bad daycares out there. We have one locally that freely admits that most of the dogs wear electronic shock collars because "it keeps things quieter".