I need to buy a new hammer drill for work. Once in a while I will use it to drill 1/8" holes in concrete floors to hold carpet fastners. (I install floorcovering) I do not want a large drill, I have a big ol' Milwalkee. I think I would like to have a small electric. I have seen them rated by amps starting at 5 and going to 8. I will only need this drill for another year, so I do not feel the need to buy the biggest and the baddest. What drill do I need and what do amps have to do with the performance of the drill.