Who Do I Invite To The Bridal Shower!

My son is getting Married Nov 2006. She wanted a small wedding. We come from a large family and have lots of friends. So its a small wedding and in her aunts back yard. Now, that the maid-of-honor wants to through her a shower I offered my house (large) to host the event. The in-laws do not want to invite people that were not invited to the wedding to attend the shower but, we have lots of close friends who want to attend because they were not invited to the wedding. So.... Do I have the shower?
They wanted me to have it within 2 weeks. I am pushing it back 30days. (I have no addrsess yet, from their side) My son`s future mother-in-law thinks its rude to invite people who were not invited to the wedding. What should I do?
I wanted a co-ed Wedding shower not a bridal shower.
Any suggestions?