HANA App Architecture doubts

Hello gurus,

I've been reading a lot about HANA and I got so excited with this.

I'm with some doubts about this technology and I expect that you can help-me!

I've been thinking about an app that needs read R/3 data, like purchases (EKKO table as.)

But that company doesn't have HANA and I want to develop the view with SAP UI5 and make persistence with OData.

Could my Hana Cloud server read the company R/3 data? Like my Hana database be the mirror of the r/3 ekko table?

How should be my architecture if I want to offer my app with HANA to the company?

If I need to make processes in R/3 like change a custom field of the ekko table, how can I do this?

Thank you guys,