The use of the word were in this construction is fading from our language as people do not understand the correctness of it.
This construction is called "contrary-to-fact" subjunctive. It is a situation in which one wishes for something that is not true.
...I wish I were able to attend (but I cannot)...
...I wish he were here with me (but he is not)...
Often the verb form in this subjunctive is not different from the regular verb we would use.
...he wishes I had gone (but I didn't)...
...she wishes he had been there (but he wasn't)...
It is the form of to be that we have to watch out for.
Remember: "I wish I WERE...."
Happy punctuating!
Margie