Hi Sameer,
I guess you should start with reading the document by Kumar Mayuresh on ABAP for HANA
http://scn.sap.com/community/abap/hana/blog/2012/12/04/key-learning--in-sapteched--abap-on-hana
It is not required to learn BW for HANA but if you are going to work on BW on HANA then only BW knowledge is required although knowing BW will help you in learning HANA concepts easily
Knowledge of BODS is a required as it is used to transfer data from Source System to HANA
Knowledge of BO will be required for Reporting on HANA
In SPS5, SAP also introduced an XS Application Server in HANA: to work with this server you need to learn JavaScript, understand OData Concepts and a bit of SAPUI5( HTML5).
SAP is offering free online course Introduction to HANA Software Development, you can learn a lot from these courses : https://open.sap.com/
You can get most of the documents form :http://help.sap.com/hana_appliance/
Visit SAP HANA Academy for Video Tutorials :http://www.saphana.com/community/implement/hana-academy
Check these links for SAP HANA Certification: SAP HANA and In-Memory Business Data Management... | SCN
SAP HANA and In-Memory Business Data Management... | SCN
SAP HANA and In-Memory Business Data Management... | SCN
And finally Get your hands on HA100 or HA200 and HA300 books
First of all get ans access to a HANA server.
OpenSAP is a good platform to start on HANA.
After completing OpenSAP course you can start learning more by watching videos from HANA Academy and i would suggest you that after completing OpenSAP course, start practicing more of Modeling, then learn User Administration, then Data Provisioning and then Reporting