Nine year old weimaraner. Dog aggression. Help!?

I have a nine year old female weimaraner. She is such a sweet dog. She knows all of her commands and is such a people dog. Not at all people aggressive (she is even good with my 19 month old brother) but with dogs its a different story. We just adopted her only a week ago and the woman told us she was friendly with other dogs and thats just not true at all. We are more than willing to put the work into fixing this problem, but she gets very aggressive with dogs and we arent sure of a way to work on this problem without putting both her and the other dog in harms way. Any suggestions? Also, we live in a beach community where there are many other dogs so this is a big issue. Thanks in advance.h