fuel efficiency?

[mexicanzero]

so i just got a 1992 legacy 2.2L turbo, unfortunately its automatic but i had no choice since i cant really afford whatever i want right now

it costs me about 60$ to fill up the tank and then its at the halfway mark after 150-160km of driving

300-320km on 60$ seems pretty bad to me is this normal for this car?
other than some obvious things like fuel leaks where should i start in my attempt at making the car gimme more distance to a tank.

i don't drive much on the highway but i'm not one of those kids that like to floor it at every light so my driving habits aren't whats killing it, and its winter here so there's no a/c on either.

oh and in the manual it says to use premium fuel will it kill the car that much if i just use regular to save a few bucks?

also i find that half the time (more so when the car is left sitting for the night or a long while) when i go to start it it takes a few seconds to start up, if i dont leave car sitting too long it will start up the second i turn the key. i've been told it could be a problem with a leaky injector leaking into the cylinder or possibly the rollover valve leaking back into the tank, in any case its a problem with fuel pressure being lost when the car is sitting. Does anyone know of a common problem with subaru's where i can start or am i lost to figure it out on my own?

thanks
-Alex