Need Joomla site updated and security issues fixed as well

Hello. I have a site that has been temporarily taken offline because I was running an older version of Joomla and there were numerous hacks attempted and some areas may have been injected with hacking material. I am needing someone that knows Joomla very well and can update the site to the newest version of Joomla and be able to keep the site looking the same with the look, feel , and function It use to be. I am also needing you to browse through the site and clean out any files that may have been tampered with and injected by hackers with code etc. so the site can run well with no areas that are vulnerable to be hacked. I am needing someone very familiar with Joomla and Joomla expert I guess you could say.