Hope i got your question right, but consider the following suggestion for working:
one database ("Current DB") that stores the real-time data.
when it comes to a size, it is dumped (or copied mdf+ldf) to archive.
and stored with time stamps (FROM-TO).
When data is needed, the relevant mdf is attached as a new "offline" database.
(you can use a connection string to attach MDF file to an SQL Server.)
and use that connection instead of the live one.
The application can run smoothly on the On-line database.
while reading, loading etc...
is done from the temporary attached and detached database files.
Take a look at : Connection String to Connect to .MDF for how to Attach a MDF to SQL Server instance.