Would it be possible to purchase just the decoders that come installed in the DCC Turnouts (left or right) so that I can convert my older remote turnouts to DCC.
If they are not available from Bachmann, I would suggest using either the Digitrax DS52 or DS64 stationary decoders.
The DS52 controls 1 or 2 turnouts:
http://www.digitrax.com/products/stationary-decoders/ds52/
The DS64 controls up to 4 turnouts:
http://www.digitrax.com/products/stationary-decoders/ds64/
Both can control either dual solanoid switch motors, or slow motion type switch motors. If you have both types on your layout, you'll need a seperate decoder to each type.
Len