thanks for the responses. i bought the antenna from eBay, you can just run a search for roof-mount antenna, and it will come up with a whole bunch of vw/audi ones for around 20 bucks. basically i just followed what i found here:
http://www.saablink.net/forum/showthread.php?t=1305
-i stretched a length of string between the back top corner of the rear doors, tucking it under the weather stripping, as you can see in the pic. (note: in the pic it is not straight, i took some time to make sure it was straight.)
-measure the string between the 2 points and find the center.
-mark the center point and drill through, first using a small bit, then stepping up to the 1/2 inch hole. (note: i had already removed the headliner from the car, but if you haven't you need to for this mod, unless you want to drill thru the headliner as well. also, right below the point where i drilled, on the inside roof of the car, there is a tar-substance mat that you will be drilling through, so don't be alarmed) if needed, you can use a circular file to widen the hole to make sure the threads fit without damage
-put the wire down through the hole and push/pull it until it pulls the antenna down so the base is flat on the roof.
-my unit came with a "grip washer," basically just a washer with 4 spikes coming off it, which are supposed to help keep the antenna located in one spot. thread the wire through this washer and place it over the threades part of the antenna which is poking through the roof, spikes upward, against the tar pad. then tighten the nut up against it, and keep cranking on it with a wrench until it won't go anymore. (note: all the while you are wrenching ensure the mast stays straight. it may help if you have someone on the outside of the car holding the antenna while you wrench from the inside.
-finally just route the wire up along the edge of the roof, around the moonroof (if applicable), down the passenger a-pillar into the passenger footwell, behind the fusebox, and into the back of the dash pocket, where you can plug it directly into the original antenna jack on the back of your radio. mine came with about 14 feet of wire, so there is plenty to do the job.
-NOTE: i strongly recommend running the wiring down the passenger side for the following reasons: 1. if you are running an aftermarket stereo (as i am) with an amplifier in the hatch area, you are running power cables down the driver's side, due to the battery being located on the driver's side. if you run power wires and signal wires on opposite sides of the car, you will have a minimum of interference in the signal. 2. if you did run the wire down the driver's side, you would have to go through the driver's footwell, which is dangerous if the wire is not properly secured and it happens to fall into the pedal area. hope this writeup helps, good luck!