I agree with Nate about the recordings. Find the guy and give him anything you've currently got recorded, the quality of the recording on your MySpace is easily good enough for him or anybody else to know what you sound like that.
Having said that I think you have 3 options.
1. Do nothing and carry on as you are. They don't seem interested in taking it further so just go with the flow.
2. Become really thick skinned and also take on all the work yourself. If you want it to go somewhere then take it there. Book the gigs, book the studio time, manage the band yourself. You could try and talk the other guys into your way of thinking though. Maybe they don't wanna try in case they fail.
3. Ditch your band and work with the new band or find something else. You gotta surround yourself with people who think in the same positive, ambitious way that you do or they will drag you down. You may have loads of fun jamming and writing with them but if you wanna take it further you'll have to change something.
Neither sound like easy choices to make but if you have ambition your gonna have to do something about it. I've been in my current band for 2 and a half years and I've realised if I want it to go anywhere then it's me that has to do something about it. I've taken on all the gig bookings, building fan base, collecting money at gigs, selling cd's at gigs. We're only a 2 piece and we both have the same ambition but the other guy has that attitude of "when are we gonna be famous" "surely we just need to book a gig and there will be 300 people there who will all want to buy our CD" "I'll be able to quit my job soon". He writes most of the riffs and we jam them to arrange songs and on that level we're on the same wavelength but I know it's me that has to do the "management" side of things.
You should check this site out, you may not agree with everything the guy says but I think he has a lot of good points to make. http://newmusicstrategies.com/