What can I do to get back the shine in my hardwoodfloors should I put aaaaaaaanother coat of polyurethane on them?

The best way is to either sand and refinish the floors OR do a screen and recoat (which adds another coat of poly).

This depends on the condition of your floors. If they are worn down and there are scratches through the color, it's best to do a full sanding and completely refinish the floor. If the floors are in good condition and it's just the shine, then you can do a screen and recoat where you buff the floors and then add a top coat of poly. If you like it shiny, you could choose semi gloss finish (or even glossy). Or for some sheen but too much, choose satin.

I would not recommend oiling oil based products that promise a glow (e.g. Orange glo, murphy's oil). These products contain wax which actually wears down your polyurethane and cause you to refinish your floors sooner (plus you will need to keep reapplying).