This may be an impossible question to answer but, if anyone can answer it, DCFers can:   I am trying to estimate monthly expenses for 2 people (and one cat) who own a 3-bedroom house in the NE Heights.  I can estimate the mortgage payment, but need help with the avg. cost of utilities such as land line phone, DirecTV, water/sewer, gas, electricity, garbage collection, high speed internet, even in…