Shave the ear flap with a mustache trimmer or a Wahl Peanut trimmer. The weight of hair can contribute to floppy ears. Teething is another thing that can cause the ears to go down. You can try taping the ears.
Here is one thread on floppy ears:
http://www.yorkietalk.com/forums/gen...oppy-ears.html
For more threads, try using Google search: Yorkietalk floppy ears