Count Unique values after being filtered

Hello.

I have been stumbling with this all day and I've not been able to figure it out.

Screen Shot 2014-11-04 at 7.36.58 PM.png

For example:
Hit the filter on "Type" and select "house" only
The value given is 4 which is the number of unique in the entire column, however that is not accurate after filter is applied
The value for unique numbers is actually 3
Also then if it is a Dwelling then it needs to be subtracted from the number in cell A13
So Cell C13 would have to be subtracted from the value of cell A13

Formula being used in cell A13 is =SUM(IF(FREQUENCY(A2:A11, A2:A11)>0,1))-C13

In this case the answer I am looking for in cell A13 is 2 however, I am unable to figure out a formula to give me that.

Help is appreciated.