puppy and dog play

Question
I have a one and a half year old dog who is very playful.  When other dogs come over to the house, she will follow them around and insist on playing.  We just brought an eight week old puppy into our home, who is very playful herself.  Under strict supervision, we have let the two play.  Today, the older and much bigger dog didn't realize her size and plowed over the pup.  Then later, she ran into the house after the pup and pounced on her.  I am keeping the two separated until I know what to do to teach the older dog how to be gentile with our new family member.  I am afraid that the older dog will unintentionally injure the pup.  I really want the two to be able to play together and be best buds.  Do I have to wait until the pup gets bigger to be able to have them interact?

Answer
No go ahead and let them play as long the little one seems to be enjoying it.  Even occasional yelps to teach the older dog how much is too much are OK.  We do this all the time, mostly with combinations such as in April our 8 month old lab and a 7 week old Golden.  Our friend has a large, male Lab that is about 5 now.  I have been very pleased how he has played with the 4 new puppies we have had since he was 1 1/2.  Keep an eye on them.  Step in if it really looks like the little is getting the worst of it.  After a bit of a time out, let them go back to it again.  

Two females in the same household can be a problem.  It is less likely if both are spayed.  You need to be prepared for trouble to break out anytime until the younger is past 3 years old.  Usually by that time, their personality has stabilized and they are unlikely to challenge the other dog.