Why is there oil coming from my engine through my air hose and leaking on to the filter?

When my car sits over night and I start it in the morning a terrible smell comes from my exhaust and out of my air vents. I just replaced my radiator and hoses two months ago however my upper hose is still collapsing. My powering steering pump is starting to go out. Every now and then when I stop at a red light or stop, when I take my foot off the brake to go. The car stalls, I have to hot the break again and then hit the gas. Sometimes when I slow down and stop at a red light my RPM's jump. My biggest concern is the oil I have noticed leaking down my air hose to my filter. I need help trying to figure out what is going on. I was told it sounded like my Cadillac converts were clogged. I'm a beginning grease head, so I do not have the knowledge needed to figure this out on my own.