You get a job, and earn the money it will take to feed and take the dog to the vet. Not to mention buy the bowls, leash, harness, collar, and toys. Oh don't forget the dog shampoo. Also make up a schedule for yourself to follow. You will need to get up earlier in the morning so you can walk the dog and feed it before school. And then after school and before your job, that you have to pay for the dog, you will need to take the dog for another walk. After work you will need feed your dog and again walk it. Depending on the breed the walks will vary in time. High energy working dogs will need about 45 min. for each walk, plus some extra playtime. Smaller dogs will need less. Now after you and the dog have both been fed you can start on your homework, but don't stay up too late as you need to get up early to take care of the dog.
gatorblu is right, also remember, you can take the dog when you move out, because you are the one who wanted it, because I am sure your parents are going to want to do other things after you move out besides take care the other dog YOU wanted.