I'm a bit unclear on your "sparge". Did you add the 3 gallons to the tun before you drained any wort off? If so, that isn't really a "sparge".
For batch sparging, the general process is to add about 1.25-1.5 quarts of water per lb of grain. Stir like mad and then let sit of an hour or so. Drain the tun completely. (Those are your first runnings) Then, add sparge water and stir like crazy. Let it sit for a couple minutes and then drain completely. (Those are your second runnings) Some people do that step twice using half of their sparge water each time. (That last sparge would be the 3rd runnings.)
For lumps, you basically just need to stir, stir, stir. If you've got a buddy helping, one of you can stir while the other pours. If you are doing it yourself, you can add some grain, stir, add some more grain, stir, and then add the rest, and stir.