"I have one revolving charge card that is old and in collections (mobil) the balance is zero on that though."

It doesn't count because the balance is zero AND it is closed.

The auto (installment) loans definitely HELP your scores, but you always need to have revolving accounts too. That's just what scores want to see, in part to make sure you don't have any habits that would cause you to use all your available credit when you don't have the cash to pay it back. You can't charge drinks to your car loan on a Friday night at the bar.

And yes, more cards would help, although in the short term the inquiry and the "new" account will lower your scores for a few months.

I recommend about 3 to 4 credit cards and a couple charge cards like Target, but obviously only for people who are able to handle the associated paper work.

The higher the limits, the lower your B/L ratio, provided you don't charge the cards up.