Web development -- 2

I need my website re-configured. The site (which is an e-commerce site) is built on core php, [login to view URL] payment gateway is integrated for payment. What I need is as follows, which is fairly simple for a good php developer. To be honest it is more of screening process to find the right person for further development of the site, which would follow once the current issues are fixed. 1. There is session or cache based issue, for some products the upload art work files gets mix up. 2. Need to improve the site load time as much as possible. Currently the site takes about 4 to 5 seconds to load fully. The site is already running on VPS hosting. 3. We have a paid third party multi file uploader customized and integrated to the site. Now what it does is when a customer uploads a file it creates a folder on the server and once the action is completed i.e. checkout or quote request the file gets saved in the folder, else the blank folders keep generating with every upload, eventually it forms a big cluster of empty folders on the server and we have to manually delete them - maybe it can be cleaned up by creating a cron job. But I am looking for a better way for this to be handled. 4. Need to fix some on page SEO [login to view URL] site is already ranking on Google on several kw. You should have through knowledge on page SEO fixes. 5. Change the font on the site. 6. Need to change the design layouts of auto emails that goes out to the customers - like the order confirmation email and order status emails etc. 7 some Minor changes in admin like csv download of orders and deleting any order entry. I know that understanding someone else code is troublesome - apply only if you are willing to do so. The site is already live and all fixes and changes will be done on a separate server and once tested and approved will be replaced on the main server. In the next stage we want to redesign and make the site fully mobile responsive and add new features to the site. But we talk about that once we finish these.