The dust has been setteling for 4 days already and Ive mopped the floor about 47 times and Ive been on my hands and knees with a towel and it still has residue. I bought some stuff called star cleen (sulfamic acid) do you think that will do it?

Probably, yes. Typically the better grout cleaners will have some acid in them to eat the top layer of the grout (and the dirt that's embedded in it) away. I've had good experiences with the acid based grout cleaners.

You should also look into a good grout sealer when you're done cleaning it.

Yes sealing is a must we were hoping for the grout to be darker do you think when I seal it it will get darker? If not other than re grouting is there a way to make darker?

I think you could probably find a stain that will work. Check with local flooring supply companies - and even Paint stores like Sherwin Williams.