To Change the Printer Default Setup?

I am using Epson L800 printer.... It is slow...Therefore I decided to buy Epson L1800 an A3 printer... so that it will print in landscape mode and the prints will be faster... But when bought the printer I found it prints only in Portrait format.... I tried changing the printer defult settings from Portrait to Landscape... but it doest accept the settings it prints only in Portrait format.... this way my purchse of A3 printer becomes waste.... is thier any solution for this.... I want to printer to print in Landscape mode my default....