salary.com is notorious for being high. Most HR/payroll people scoff at the results. They are not true compensation surveys as they just take the information as entered from people you as their data source. That can truly skew the results. If you feel it is true, the only way to test it is to interview for other jobs and see what kind of offers you can get.
Your employer has a pay range for your position so obviously they have done a compensation study in the past. You might consider asking them when they updated that last with the market. Just realize that many salaries in the market have stagnated due to the economy and the high level of unemployment and high level of qualified applicants. So it is possible if they update that your range may actually decrease rather than increase! The last few years, I have seen very little in the way of upping pay ranges for even a basic cost of living adjustment. I went from a pay decrease to 3 years without any pay increase. And often there is pay compression -- that is, those hired from the outside often come in at a higher level than someone who stays around and gets basic increases.
It is very possible that your employers brought you into that pay position knowing that they would increase your responsibilities and have you manage others ....just those two things might be the reason that you were hired at the top end. So it could be viewed as you were actually overpaid in the first part of your 2 years.
What you are truly asking for is a promotion to the next level. I would put together what you have accomplished over the last 2 years in your current position. Service time alone is not enough in most companies. Think like you were putting together an updated resume and going for an interview. What would you tell them you brought to the table in the last two years? What are the requirements for the next level and do you meet them? If not, figure out what you are lacking and work on that. And it might just be that there are no current openings at the next level, but you can let them know that you are interested.