Not that hard, you bumped into one (Marc) on your first post!
Luckily for you the laser bit of the thing you bought, isn't the expensive bit (that's the BOX),
which is really quite reasonable.
My advice is to buy an Olike 445nm kit module + driver from (also TTL) from fleabay stick it in the box instead of the green and wear sun glasses to watch it project onto a wall the first time.
Analogue would be better in the long run, but your DMX into the LW projector would probably not know how to tell it what to do.
You have a steep learning curve ahead if you want to go RGB, and maybe better to fix the problem first, (with interesting results), then learn a lot more before buying more stuff.
It is difficult to DJ and fiddle with laser stuff at the same time.
What you bought was CHEAP, what you got was CHEAP, AND didn't require thinking about.
With what I suggest above, you need to think a little bit (safety stuff), do a little bit, (take out green put blue in) and you won't have to babysit the results at all. (except for safety).
The "input adjustor" (bent bit of aluminium) is quite easy to bend or shim to get the height right, the beam will be big enough to spill over both sides of the scanner mirror (easy allignment).
You will also find it dead easy to sell on.
With all the losses in the original setup, you will still be getting three times the power you had before , and the colour will be right in "fashion".
Cheers!