Thanks ZippyV and W3bbo for your advise .. i will try to purchase upgrade license ...
Hopefully no complications during install .. 
and yes I was really disappointed by the technical proficiency and attitude of MS Helpdesk which was specifically made for Licensing/Technical queries.
When i called them last monday they escalated the case for providing more information and promised to contact me within 2-3 days.. The helpdesk did not callback as promised and had to be given reminder(s) and finally the answer they gave were really non-technical that "I will not be able create executable with VS2005/2010" after upgrade 
