I flew 1500 hrs in Dash 8's for Mesa Airlines in the US in the 90's, was about to upgrade to captain when I got a call from Emery Worldwide to fly the DC8 and 10.
To me it sounds as if the OP has a lot more than 1500 hours, however to get a $40,000 type rating means that you have to get about 50 days of work in the first year to pay for the rating, average daily rate for G4 right now appears to be around $800, before you start to earn any money to put food on the table
Mutt