[V8] Oil presure really low

[quattro]

I noticed my oil gauge creeping below the  5 bar mark last week and figured it was time for an oil change. I've been adding a quart of oil at every fillup, so needless to say....its been a while since a full oil change has been done on the car. Now with a fresh oil change and filter and one can of 8-cyl engine restorer(don't laugh, it was recommended by more that one reputable lister) the oil gauge no reads  1 bar at idle(600 RPM) and bottoms out @ 4-4.5 bar above idle. I now have the pan dropped and noticed  what looks like dirty tranny fluid at the bottom of the pan. There are no abnormal noises coming from the motor or oil pump area. I first suspected the stuff on the  pan was the engine restorer, but that stuff is blue in color, but then again....it did have a matrix type look to it( OK metal flake.....but I'm sure engine restorer doesn't have metal flake in it) Any thoughts guys? I'm hoping its a bad oil sender. Like I said....I have the pan down now......so if you guys got something to suggest me look at, it would be greatly appreciated