Oil leaking. Need advice!

[06 X5]

I have just recently purchased my first BMW, an '06 4.4i X5 with roughly 125k miles on it.

First off, let me say, that I absolutely love this car! I never imagined an SUV with such a sporty feel. IT'S AMAZING!!!!

I have spent the last few weeks using the good ol' search function and I have already found a ton of useful unformation, but I do still have some questions.

I have been experiencing a pretty serious oil leak (PO said, "it leaks a little power steering fluid.") that is dripping down to the exhaust and making a foul smell, plus it looks like crap driving a nice BMW that smokes!

I plan on doing everything at once. I am pretty mechanically inclined and am confident that doing the job wont be too tough with a little guidance from here.

Here's what I have on my list so far:

1) Oil filter kit (11-42-7-511-161-M45)
2) New oil Mobil1 5W-40
3) All new spark plugs NGK BKR6EQUP
3) Valve Cover Gasket Set
- Left 11-12-7-513-195-M30
- Right 11-12-7-513-194-M30
4) Timing Chain Case Cover
- Left 11-14-7-506-425-M30
- Right 11-14-7-506-424-M30
5) Alternator Gasket P/N/ 12317507808

That is all that is on my list so far. I have read about the OFHG (oil filter housing gasket), but I'm not sure if that pertains to my car. Also, what is the oil separator and should that be replace as well? Lastly, Is there a "spark plug gasket" or something of the sort that goes on the valve cover around the spark plug holes? Lastly, what spark plugs do you guys recommend?

Thanks in advance! I know I have a long learning cure ahead.