when you wired the lights up to the switch did you use a relay.
When you say your back lights are on, which ones are they, but it sounds like you have managed to create a short between the battery and the lights on the back.
take out the switch and undo what you did to it, should go back to normal then...hopefully.
As for the dash lights, you my have blown the bulbs or the fuse by an inrush of current caused by the new wires you've put on.
Stu