SM library has a fast respawn timer for some odd reason. You'll always have some respawn if you clear it without a 70 mowing everything down.

Not sure what your problem is with killing them fast enough. Lightning, chain lightning, shock, melee, ect. Maybe drop some fire nova totems to help your dps out. Target monks first, they're the only ones who really hurt.

Work out your healing macros before you try another run. There are hundreds of ways to do them. Go check the macro forums for your answers there.