1993 subaru impreza headunit

I have two speakers, both of which are wired in to the unit. There was another thing i noticed tonight when i was driving, that is when its turned up the screen dims on the unit as do my dash lights...so it must be drawing  a bit from my battery.

Sounds like you need to run the wire to your battery. It needs to be 12 or 14 Ga. And remember you need to put a fuse holder and a 10 amp fuse at the battery. The fuse holder located at the battery is very important.

Could u kinda go over how i would do that?

The following is assuming your battery is in the engine compartment.  First thing you need to do before doing this or any other project on your car is to disconnect the negative terminal of your battery.   Get a piece of 12 guage wire, long enough to reach from the back of your radio to the positive terminal of your battery. Get a fuse holder and a 10 amp fuse also. Connect the fuse holder to the positive terminal of your battery. Do not put the fuse in the holder till the end of the job. Connect the wire to the other end of the fuse holder. Route the wire toward the firewall of the car. Look for other wires going that way and tie wrap the wire to the existing bundle of wires. When you get to the firewall, you need to find a place for the wire to go into the car. If the harness you ran the wire with goes into the body of the car, you can try to go in with it. You will need to poke a hole through the grommet that the bundle of wires go through. Do not use a knife or anythig that could strip insulation off of the wires in the bundle. A  #1 phillips screwdriver works good in a lot of cases. Do not force it through anything other than the rubber of the grommet. You need to look inside the car where the bundle comes in and make sure you are not going to shove the screwdriver through the bundle of wires. Remove the screwdriver and insert the wire through the hole you just made. Go under the dash inside the car and pull the wire through till you have all of the slack out of it. You then need to be careful not to run the wire where it will interfere with the brake, clutch, accellerator, or the steering linkage. Run it to the radio  and connect it to the yellow wire of the radio. Take the wire that had the 2 amp fuse in it and you need to tape the end of it so it will not be able to ground out. Leave the fuse out of it as an extra precaution. Now we can put the fuse in the fuse holder at the battery, and you should be ready to go.