Got A Promotion? What About The Pay?

This is more of a rant so, I apologize for going a little off topic. I have been working at this company for over a year. Not to brag, but I pretty much do everything at some point each week. I mean, I have knowledge of over 80% of the duties of other employees with higher and lower positions than mine. I like the people I work with, and that is the only reason that is keeping me there as I have been screwed over my pay over and over again. I got a promotion in June, and my pay raise is scheduled to take effect in October and I am highly disappointed. They are going to pay me peanuts! Seriously, the pay I will receive is far too low, not only for the amount of work I do but compared to others in the same job band. I tried my best to negotiate, I am aware that if I were to apply at another company for an even high position I would get a lot more. I have been approached by recruiters but my loyalty to the company stood in the way. What should I do? Any suggestions?