<human>: Can you give me the gist of the text in a nutshell?

I've started as a contract employee for an insurance company 2 months ago. One of my coworkers who is also a contract employee is leaving this week after a one-year stint with the company. Last week, I had a short talk with my boss (initiated by my boss) and discovered this contract worker was paid a much higher rate. Her tone was indicative of it being "too much". 

When I was hired, I felt that the wage was too low, but I took it anyway not feeling like I could negotiate as I was new to contract work. However, now I am seeing how much responsibility and ability this job requires and I feel like I should be paid more. I'm not only taking all of the work my coworker has, but I have extra responsibilities on top of it. The problem is, I've never been a contract worker before. I'm not sure if I should even try to discuss a higher wage. My contract is good through the end of the year. I will either have it renewed or it could possibly develop into a new position. I'm wanting to ask my coworker (who I am replacing) what her salary is in order to gauge how much seems "too much" to my boss. Since she is leaving, I feel it will be easier for her to discuss it with me.
<bot>: Coworker is leaving the company. I am taking on all of her work plus my own added responsibilities. I want to know how much she is paid so I can better negotiate my possible next job within the company.