Dear sir i have a empire/corcho 1500 btu heater and i have a 70 gallon tank of propane tank but the heater says natural gas can i do this or do i have to use a conversion kit and do i do that and where do i get this and how much do they cost but can i run it with propane

First off, yes you can convert it to propane. The difference is that the orifice, which should be in the conversion kit, has a smaller hole for the gas to pass through and needs to be changed. Secondly, the air consumption on propane is greater than that of natural gas and for that reason you need to open the air venturi, usually to the max to allow the largest amount of air to enter. Don't overlook the pilot light as well, it also needs to have a different orifice installed. You can find new orifices and/or conversion kits at the store where you buy your propane, assuming it's not a big box retailer. Go to a local propane supply location for the parts. Another option is to go directly to the manufacturers home page and order the propane orifices.