Hello,
I'm an independent web developer, I can check your site free of charge while I look for an answer to your problem. Perhaps the problem is a compatibility issue since you mentioned you were upgraded in PHP, my bid is a conservative one, knowing what the problem is I can give a better estimate.
I can start right now, my timezone is PST and can keep coms through skype or chat.
Please contact me via PM if you have any questions
Regards