Your not screwed but it will cost at least $600 for the additional equipment needed and it may not be compatible with the upcoming MPEG4 dish.

Take two outputs from the Phase III dish and run them into a stacker. Take the other two outputs from the Phase III dish and run them through 22khz tone generators and then into a second stacker. The existing cables will carry all the channels to the basement. Take the first wire and run it through a splitter and a de-stacker and into the Sat A inputs of a multi-switch. Take the second wire and run it through a splitter and de-stacker and into the Sat B/C inputs of the switch. You can also diplex an OTA signal onto one of these cables as well.

-Robert