the brand is really irrelevant as far as the oil goes some good brands are Castrol Mobil Valvoline Pennzoil
i would think it probably takes a 10w30 you can check the owners manual to be sure
if you change your oil frequently and regularly you can get by with conventional oil but remember unlike synthetics it will start breaking down after about 3000 miles so keep a regular schedule
as far as the filter goes I would suggest the Wix brand for many reasons but too much to write out here
also make sure you replace the air filter every other oil change as much as gas costs these days you need all the fuel economy you can get
BTW i love those BMW's
good luck