For the 3.0 it's 6.9 quarts or 6.5 liters with the filter.

Dealers sell synthetic OEM engine oil and they are 5w30.

Some resources for changing oil. If you're not sure, ask.

http://www.xoutpost.com/bmw-sav-foru...hange-diy.html
DIY - E92 Oil Change - BMW 3-Series (E90 E92) Forum - E90Post.com
http://www.xoutpost.com/bmw-sav-foru...ics-added.html
http://www.xoutpost.com/articles/x5/...w-x5-3-0i.html