Hire a WordPress Developer

I have a website at https://reikiforliving.org. Currently there are a number of problems that need to be fixed and it seems that an updated theme is required as a first step. In updating to a new theme, I would like to retain all of the same look and feel as the current site in addition to all content. I am using plugins from acuity for scheduling, a shopping cart (which does not seem to be working), as well as contact forms (also not working presently). Pages load properly sometimes and at other times are rendered unreadable. I need the site thoroughly tested as well once the transition is finalized. In addition to this work described above, I am searching for future assistance with search engine optimization and search engine marketing. I will require assistance with the creation of landing pages as well as configuration of Google analytics. Please let me know: 1) What specific tasks need to be done to get my website onto a new theme. 2) Provide an estimate for the work required to complete the tasks. 3) Provide some examples of relevant experience working with Wordpress sites. 4) Finally, please let me know what type of SEO/SEM/Analytics work you have done and if you think you can help with that as well. Candidates for the next stage of discussion will be selected based on the quality of communication and thoroughness of proposals.