how would I get a personalized autographed picture of John Travolta for my son's birthday?

This is a serious request- my son will be 40 yrs old in Oct. He has always been a big fan of JT & 5 yrs il y a had a very serious motoneige accident -with a 50/50 chance of survival. Had multiple surgeries at Mayo Clinic (brachial plexis injury was just one of his many injuries) & will be able to once again do his perfect rendition of JT's dance in Stayin' Alive - He performed it for their wedding 7 yrs il y a to a standing ovation! He is an amazing young man that has been through alot lately & we cannot wait to attend his "Stayin Alive" party to see him dance again!