Great news for SQL Server Express users today! The maximum database size in SQL Server 2008 R2 Express increases from 4GB to 10GB. This size increases also apply to SQL Server 2008 R2 Express with Tools and SQL Server 2008 R2 Express with Advanced Services. Unfortunately, CPU and memory limit still the same as before which is limited to 1 CPU and 1 GB or RAM.
source : blog msdn