Failed to upgrade SQL 2008 express to r2 version

Dear Guys,

My SQL 2008 express database size almost reach 4GB, I try to upgrade it to 2008 r2 express version.

But after upgrade, the SQL database instance version seems remain at 10.4.6241.0 (2008 sp4) status.

If anyone can help me to solve this issue, many thanks.

Product features discovered:
Product Instance Instance ID Feature Language Edition Version Clustered
Sql Server 2008 SQLEXPRESS MSSQL10.SQLEXPRESS Database Engine Services 1033 Express Edition 10.4.6241.0 No
Sql Server 2008 R2 SQLEXPRESS.INACTIVE MSSQL10_50.SQLEXPRESS Database Engine Services 1033 10.52.4000.0 No
Sql Server 2008 R2 Management Tools - Basic 1033 Express Edition 10.52.4042.0 No