Oil leak, hardley any power to the car, and now my brakes are not really braking!!

[smokeyh]

I am trying to get my car working, my car drives, but it has a really bad oil leak, the bottom of my car is covered with oil. It sounds like the car will die at any minute. I've gotten a lot of maybes from different mechanics, but I can't really afford to go get this and that done, and not have it fixed. Now my brakes are feeling like it's not working, the break fluids is full, looks like my brakes are fine, when I brake I have to pump it a few times before it works. I messed with the idle screw and it made my engine less shakey, but my car feels like the power is not all there. Looks like there could be a clog or something somewhere. I had changed my alternator, my starter, and now this big oil leak is causing a lot of problems. Anybody have any idea and affordable way to fix this!!! Help! I'm trying to get to Vegas, that's an 8 hour drive up and down, from where I am. Also, alot of the mechanics keep telling me to do a major tune-up on my car, is that a good idea or just a waste of money.???