you cannot explicitly move a specific object between files in the same filegroup, but you could add another file to the filegroup and data would begin to be written to the new file on a proportional fill basis.

You could also create a new filegroup on the new disk and move the table data by rebuilding its clustered index onto the new filegroup.

Perhaps you should take advantage of this situation and think about what would give you the best performance advantage with the extra disk, moving the log file, separating the data from the non-clustered indexes for the table or moving off a table which is frequently joined to other tables.