How to Clear the Database Transaction Log and Reduce the Size of Transaction Log File In sharePoint 2010

     we were using MOSS 2007 before and right now we just migrated to sharePoint 2010. I am Facing an issue that our content database transaction log file is more than the primary data file. 100gb is sql database and it is full Now. Give meh the best solution

How to Clear the Database Transaction Log and Reduce the Size of Transaction Log File In sharePoint 2010 .

Can any one tell me how to increase it upto atleast 200 GB

I am looking for the guidance from seniors and the experts in this situation