I assume that since it says Russell BMW that you are in/around Baltimore. Find a reputable independent shop to fix the items. There should be plenty of both good and bad indy shops in the area.
Oil leak is not due to a bad O-Ring around the cap. It's due to the gasket which attaches the filter housing to the engine. Shouldn't be too expensive at an indy.
Transmission leak - have the indy look at it. I'd have him change the gasket which will also result in draining most of the transmission fluid. Again, go indy. I'm pretty sure that the car has a ZR transmission. If so, have the indy use Castrol Import Multi-Vehicle Trans Fluid, as recommended by Chriztofor here:
http://www.e90post.com/forums/showthread.php?t=367729
Much cheaper than the dealer ATF and just as good as it meets Shell M1375.4 specs.
If you've got a GM transmission, have him change the gasket and put in Dexron VI. Any Dexron VI will do; the manufacturing specs on it is very tight. I used Walmart brand here:
http://www.e90post.com/forums/showthread.php?t=573490
As for the rest, in order:
Buy new rims. Consider buying used matching rims from someone who is putting new rims on their car. Just make sure they're not bent. Do this prior to wheel alignment.
Get 4 non-runflat tires and throw out the two bad rims when you get the new tires. I recommend shopping around for a good all season radial. Something like the Continental Extreme Contact DWS; $106 on TireRack.com. I have the Extreme Contact DW (summer) tires but I live in Tucson. Love 'em.
Get the control arms replaced when you get an alignment.
In priority order, I'd have things done (should money be an issue):
Rims/Tires/Control Arms/Alignment - all done at the same time.
Transmission leak
Oil leak
Just going with Castrol ATF, newsed (new used) rims, and non-runflats will save you big bucks off of the dealer's estimate.
Just my two centavos which are worth a lot less after QE1 and QE2.
Good luck to ya.