Uncomplex's Mailplane 2.1.9 offers the capability to drag .webloc and .mailloc files into Mailplane to insert the URL encapsulated in the file into the message text. But the real reason to upgrade to Mailplane 2.1.9 is the fix to the problem that attaching files via drag-and-drop often didn't work if you had also upgraded to the recently released Flash 10.1 (which you want to do, since the previous version is a security hole; see "Adobe Flash Player 10.1.53.64 Blocks 32 Security Holes," 11 June 2010). The update also fixes a problem dragging text clippings to Mailplane, fixes a focus problem caused by upgrading to Safari 5, and improves performance when composing replies. Release notes are available. ($24.95 new, free update, 7.7 MB)
Extract Directly from Time Machine
Normally you use Time Machine to restore lost data in a file like this: within the Time Machine interface, you go back to the time the file was not yet messed up, and you restore it to replace the file you have now.
You can also elect to keep both, but the restored file takes the name and place of the current one. So, if you have made changes since the backup took place that you would like to keep, they are lost, or you have to mess around a bit to merge changes, rename files, and trash the unwanted one.
As an alternative, you can browse the Time Machine backup volume directly in the Finder like any normal disk, navigate through the chronological backup hierarchy, and find the file which contains the lost content.
Once you've found it, you can open it and the current version of the file side-by-side, and copy information from Time Machine's version of the file into the current one, without losing any content you put in it since the backup was made.