Customise an existing hosted Elgg

I have an existing Elgg, hosted web site. Created with SImplescripts, thru cPanel. I want to add the following functionality using existing free (paid if free not suitable), themes and plugins to enhance the site: 1. Event Management plug in. For 1. Accessing the Elgg Member database and selecting based on variable options like tags, Groups etc, [login to view URL] the invite letters or emails, simple ,little graphics, maybe Google Docs would suffice. 3 Sending invite letters, , 4. Tracking RSVP 5. Marking Attendence sheets and attendee feedback 6. Putting up the Seminar presentations, documents, videos, audios, on public sites like Slideshare, Youtube, etc. 7. Linking up the above, so Members can carry on the exchange of ideas in the discussion forums. 2. Plugin for doing simple eCommerce transactions, by Network members, of posting a product, with the price, or Points, buying, selling and keeping the Members balance, in points. Possibly link up with a Std eCommerce package, like OScommerce, or Magento. 3. Plugin for buying Points using Paypal or credit cards, in various currencies, and a conversion into Points. Stage II. Web conferencing of seminars, and recording lectures whiteboards etc. Prefer using Open Source sw like BigBlueButton, or a service like Adobe Classroom, or GoTo Meeting Stage III. Convert the above into a virtual appliance, Turnkey Linux (TKL), Bitnami, JumpBox other equivalent platforms which can operate on a LAN server, or on the Cloud (Amazon, Right Scale, Eucalyptus, VMware etc), or a Private Cloud Stage IV Maintaining the Cloud based servers on a monthly basis. Pl. give your time frames and budgetary costs for the above alongwith execution costs for the Stage I, pl. give a fixed cost.