Web development

I need an existing website rebuilt. I need you to build my online store. I use zen cart. Established 7 years and going well Website is a bit clunky and slow and although it does well it does need improvement.  There are a couple of websites which look nice and would like to have mine converted to look like them in some ways. Logo and everything else needs updating and am willing to help. Am happy to keep the same logo though so not a deal breaker. Need fast checkout with PayPal and also thinking of sage pay or world pay to. Need some form of easy populate facility added and other visually nice tweeks. I need a new cart that is ultra responsive over all platforms or a new website.....open cart or another type that will do the job. I need the website to be fast and quick to load and have lots of cross selling and upselling capabilities at checkout. I need my emails sorting out as I get lots of bounce backs and customers complain of not receiving order confirmation and passwords. There are lots of images on the website with many thousands more to come in the future so need the website to be futureproof and to handle existing images well as this will slow down loading. I want Internet and Google friendly urls There may be other jobs to. Sounds like a lot but I know from past work that lots of these tasks can be done very quickly and easily.