I need an email marketing strategy and implementation plan and management

we are a national online estate agency which produces circa 600-700 leads per month. We also have circa 15,000 email contacts we have generated in the past two years in our system. We dont have any kind of systemised email marketing.
We would like to install a comprehensive email strategy going forward. We would like the email marketing providor to integrate with sales force crm which we use to manage our incoming lead contacts and dezrez which is an estate agency software package used to manage vendors who come onto the market with us.