Roadmaster was a great car produced by Buick and I can understand your Fiances passion. But like the last post said, gas is going to kill you and to be honest, finding one in really good condition is going to be hard. We see quite a few showing up in the as-is lanes at auction unfortunately they are simply too rough to even toy around with. Finding one in good condition for $2500 is going to be hard.
Best of luck.