Convert Drupal 6 site to Drupal 7

We have an existing website in Drupal 6, with a custom design and theme customized for Drupal 6. I want the site converted to Drupal 7, and the existing design/theme configured for Omega responsive css. I will provide the files so you can work locally; I will install the new site etc, but want help in case there are any unforeseen issues with server. I will continue to maintain the site and want explanations for what I don't understand re conversion and theme, so I can deal with it in future. No custom modules, only regular Drupal ones. CCK and Views are used fairly extensively. We have an e-commerce implemented but not used (simply not activated). Ask for more details if needed. I have actually gone through the upgrade process, and got the site going in Drupal 7, but there are fields which have not converted (images) and I get errors which I believe are related to Views. My php skills are too poor for this. We use webforms and I need to be able to keep the data. MUST communicate well and keep me informed at all stages. I don't know what is reasonable charge for this so have chosen one simply. Don't know if hourly would be better?