I'm not familiar with the marker or the regulator, but depending on where the hose will be connected to the regulator, you might need one of them elbows to make the connection between the hose and the regulator a little less forced.
From the pic it's pretty hard to see how the hose at the moment is connected to the marker. To install the reg you will need a so called ASA (air source adapter). This has standard threading and will allow you to simply screw the regulator into your marker. To find out if you have one of these things, just unscrew the hose. If there is a hole with threading into which you could directly screw your gas tank, you're fine. If not, you'll need to convert your marker a whole lot more...
