Thanks @g tsuji. I checked your reply just now and yes whatever you have suggested is the perfect solution. Last eve I was trying to find the solution and I came across the same link you had posted here.
And I could solve my problem. still thanks for mentioning the link.
I added <style>@page {mso-page-orientation:landscape;}</style> in my .xsl file to set the page Orientation to Landscape.
and print settings to FIT ALL COLUMNS of generated Excel file on one page i have added following code
<x:WorksheetOptions>
<x:FitToPage/>
<x:Print>
<x:FitWidth>1</x:FitWidth>
<x:FitHeight>1000</x:FitHeight>
<x:ValidPrinterInfo/>
</x:Print>
</x:WorksheetOptions>
Finally could able to make it.