how to reduce DB size

Hi,

I am the happy owner of a SQL express 2008 R2 holding my DB.

I have my DB primary data file at 7 GB

In DB properties, I have initial size of primary db at 7022 MB, autogrowth = by 1 MB, unlimited.

I query table sizes with :

select object_name(id) [Table Name],
[Table Size] = convert (varchar, dpages * 8 / 1024) + 'MB'
from sysindexes where indid in (0,1)
order by dpages desc

total size of all my tables is then 1171 MB

I do shrink / files / file type = data => available free space is 0.25 MB

I'm afraid it will hit the 10 GB size.

How do I reduce the DB size ? it is possible to change the  initial size of primary db ?

thanks