Modernise our existng website make compatible for mobile devices HTML5 and INCREASE TRAFFIC!etc

Modernise our existing website make compatible for mobile devices HTML5 etc. Our HOST just told us the following about our site; ""The server has PHP 5.2 while newer PHP 5.3, 5.4 have been developed. Every version changes some of the functions and the methods they function. As a result sometimes PHP scripts don't work on servers with newer PHP versions. You will need to contact your code provider and ask them to change the code and update it according the new versions of PHP and probably MySQL because eventually outdated versions will stop working and we won't be able to have them on any servers."" We want our site to get more traffic and be future proof, currently we incorporate "Flickr" photo slide-shows within the site. This is simple for us to delete and upload new photos but we feel it is outdated and we want a new format maybe using 'Flash" for the slide-shows or the ability to have HTML5 videos inserted easily. The interface for us to use must be simple and straight forward as we are NOT TECH-gurus. We want a site that is fun to view and easy for us to update. We have maybe 30-40 apartment listings which we need to update several time a season. Our current web site has been good for the last 4 years but we need to get with the times to stay ahead of the competition., our site is a student housing management site in Ontario Canada. It is www.queensrentals.ca. Accepted bids will provide a list of all updates/changes, and provide an itemised detailed list of what we can expect to notice different on our finished new site. Also screenshots of a proposed new layout for the main page layout would be beneficial. We need work completed and help getting it on to our existing server ALL with 6-8 weeks approximately from date of agreement reached. Also some form of guarantee we get seriously increased traffic within 60 days from the new site being put online. And free follow up tweaking of any bugs or minor issues or alterations within that same 60 day period..