You can find blowers/vacuums at Home Depot or Lowe's.

Maybe you can consider using a different type of mulch. The shredded hardwood mulch usually stays in place. If you get enough of it you should be able to cover up the mulch already in place.

I'm definitely going to check out those places. It's hard to tell based on online reviews if the products will work for my purposes, though. At this point I can't really cover up the existing mulch, but if we use mulch in our backyard I definitely won't buy that kind.