Daily Deal Software and Website like Groupon

We are looking for website software similar to [login to view URL] to launch our own daily deal business. We have been looking at many of the scripts available for purchase on the Web but are unsure which to choose. The project is to either provide this software/script/website package or to provide a recommendation of an existing daily deal software/script for us to purchase. If you provide recommendation and reasons why we should select an existing script, we will use your services for customizing the script to our brand and ongoing support as well as upcoming website development projects. We need the site to be live by the end of this week. Some requirements are: - PayPal integration - Daily email template blast integration for the deal of the day - social networking support - live chat integration (optional) - mobile phone support (mobile website or iPhone app) - gift certificate generation (including numbering) - Ability to limit number of certificates available for a given deal - Support for code updates and bug fixes