In order to ease the housing shortage, the city government decided to give landlords who provide rental housing a subsidy of $5,000 for every 100 square meters rented out. Assuming that the unit of quantity Q is 100 square meters, the demand curve for renting a house is Q=500000-10P, and the supply curve is Q=15P.

(1) Calculate the pre-subsidy equilibrium quantity, the price paid by consumers, and the price received by producers.

(2) Calculate the post-subsidy equilibrium quantity, the price paid by consumers, and the price received by producers.

(3) Draw a graph to illustrate the excess burden of this subsidy, and use the graph to calculate the excess burden.