Killing Crabgrass on bare soil?

Recently bought a new house & had the old sod/yard removed by a Bobcat. The yard and sides of the house are down to bare soil for the most part and I've noticed that some areas are pretty thick with the crabgrass coming in. I can't do any damage with a hula hoe and Round-Up seems to kill the top portion only but not the root. I don't have any grass yet but plan on putting new sod in within a year or so, maybe longer if I need to wait. My question to you is, what works best to effectively kill crabgrass and where can I find it. I'm guessing that what I'm looking for you can't just find at any Home Depot or Lowe's or anything. I want grass to eventually be put in and grow over where some of these patches are but if I have to wait a lot longer to let the weed killer do its job, I'll wait. I need something pretty strong to kill this stuff. I'm just tired of it taking over the bare soil and making it look like I have tons of weeds when its just a crabgrass issue spreading like crazy. Thanks for the help.