No problem. It's what is called "paying back" into the forum that has saved my butt so many times. No problem at all. There is a lot I still need to learn as well, but just been through this myself, so I can explain-b/4 I forget.
This is the easiest repair to do- fear it not and yes,you may drive your car with no issues other than you will not have active ABS, ASC, or Speedo. So, you will essentially be driving a car that was made before anti-lock brakes & stability control were invented or widely in use-anyway. Just don't drive over your head. The BMW has pretty phenomenal stability and brakes even without these systems, but obviously be careful in rain, etc. Otherwise, you are not in any rush. I believe you will not put any miles on the car as you drive. I replaced mine pretty quick, but I can not tell you if you drive it too long w/o a working speedo and odometer whether you risk setting a mileage verification code which might not be good. I don't believe this will occur, but the car has phenomenal "brains". Let's just fix it.
Go to the place of your choice and order a rear wheel speed sensor. May be called an ABS sensor, but it will be part # 34526756376. $82 @ the source I checked. You may want to use EAC tuning who support this forum (Mark or Jared). They are delightful to work with, support this forum, and will give you excellent support should you have a question. Prices are great. You might find cheaper, but you will not find better folks to work with. Priceless as the commercial says.... They will even tell you if it is a part they feel they might not be as competitive on. They use only OEM or equivalent suppliers so you might pay a couple bux more, but you will get it back + in service.
Start by removing RR tire. Use a decent jack, not the trunk jack. If you don't own one, get one. Get a deal on a cheapo jack and jack-stand kit if you can't afford better now. You will be slightly under the car. You will see one or maybe two wires leading to back of brake area. I hope Qsilver7 or someone with more time and better at hosting pixs will jump in, but you will find a heavier wire about the size and shape of small coax cable leading into the rear wheel spindle area. The sensor itself is held in with one or two metric allen screws. If at the end of the cable you do NOT see one or two allen screws, you are looking at the wrong part. remove the allen screw which is like a 3mm metric or thereabouts. This is all that is holding the sensor in. It will be stuck it there good and is plastic so don't get heavy-handed removing. Use some rusty bolt loosener. Look, buy the sensor. Once you have the new part in your hand a lot will become more clear. Order the part, get a jack and jack stand handy and we will go from there. You will have time to get pix and find more helpful posts. I ramble! Sorry.Drive the car, get the part, get your tools, and it will take no longer than 1/2 hour to change. If we guessed right the first time, you'll be done. If we guessed wrong the first time, we wil go from there. I check forum daily as I am in a job hunt. Ok?