Most cars of your type have blank grommets in the firewall where there are allready holes available for certain options and dealer anticipated modifications. On the drivers side, pull back the lower dash, carpet, and kick pannel area. look right arround or just slightly above where th steering colum goes through. On the passenger side- remove the lower dash trim, pull back the carpet, and look in the area that would be directly behind your glove box. You are looking for basically a black plug. Also, get a flashlight out and crawl under the hool and look along the firewall for the same things. They ARE there. Just be sure to check out both sides once you find one ot be sure that it is clear. In most cases, you can remove the rubber plug and just punch a small hole into it and run your power wire through it and re-insert the plug back into its hole. most parts stores also sell rubber grommets with various hole sizes in case you need a newer one. You absolutely MUST have something between the metal of the car and the wire though! Saftey first! once it is in the car- it is all down hill from there!
Take it easy,
-zane