I would try to find a social skills group (often they are run by speech therapists). Michelle Garcia Winner's social thinking books are supposed to be really good as well: http://www.socialthinking.com/books-products/so...

Social Skills groups, The Book by Carol Gray, social Stories gave me alot of tips. Provide lots of opportunity to work on socialization. Keep in mind mild autism at the highest level is a social disorder. She may stuggle for sometime with this aspect.

Social stories may work. Or find books about being a good friend. One reason many children with Autism prefer to "be alone" is because they aren't wired to be PC and just go along with what others want. Often they want to do/play what they like. Many have a very hard time "going with the flow" of others.

You are really on the right track! You've essentially done one of Michelle Garcia Winner's techniques known as a "social autopsy" which involves processing a situation after it has passed and making suggestions for the future. Social skills groups are great, but your coaching will do far more. Try to attend one of MGW's workshops if you can (they are all over the country) and purchase some of her books/dvd's if you can't.

dance lessons/dance group; swim teams; girl scouts; soccer and yes Michelle Garcia Winners books / programs are great.
you are looking for activities where talking to your peers or teammates isn't a huge part of the activity. that is hard for her so find things (like swim team) where she can be a part of the group but standing on the sidelines and chatting with team members isn't a major part of the event.