You deserve far greater compensation than you currently receive. Given the economic constraints of the firm, you shouldn't be paid significantly more.
Every negotiation is a competition between contrasting views of reality.
To be paid what you deserve, you have to persuade your manager that your version of reality is correct. To earn more, you must show your company that your market value is actually greater than your current salary. To do that, find out what the market is willing to compensate a person with similar experience, tenure, skills, and credentials. To find out what others in similar jobs earn, start by working your contacts. Ask your network of business colleagues, inside and outside your firm, how they are being compensated.