You can’t do this dear without renewing XYZ.in. The only way to save your traffic is to renew xyz.in and then make a blog with that domain using Blogger and then, install redirection script that simply redirect xyz.in to xyz.com.
Renewing a .in domain does not costs so much. So you can easily buy It. You have to buy it only for one year because after 1 year, xyz.com with take place of xyz.in and all your visitors and subscribers got to know that you have changed the domain.
Tip: Install a sticky bar after buying your new .com domain. On that bar, write ‘Bookmark Our New Domain! xyz.com’ so all your visitors will got to know fastly that you have changed your blog’s domain.
Here is the redirection script you need to put on section of your template’s html:
location.href = 'http://xyz.com';
*Change http://xyz.com/ with your new domain
P.S.- I have changed the topic’s title.
Hope It’ll Help!