This lays to rest the opinions of those who say that guys can just have sex without emotional attachmen.
You've Broadened Your Taste in Women
Welcome to the big complicated world of feelings and relationships. I note that you're also learning that your tastes in women are somewhat broader than you previously realized. Now if you and she were just on the same page...
Here's what I think: She needs to get over that ex, for sure, but what is it that makes you realize she's still hung up on him? Point these things out to her, gently and politely.
She Can't Express Herself
I would tend to agree with you on not putting too much weight on her proclamation of love, but then, she may not have as rich a vocabulary or extensive experience as you. This is certainly likely considering her age and dearth of sexual experience. I'm not saying she should have more sex with you or anybody else, just that she may not be able to express herself and what she's feeling in any way other than to say, "I love you."
I believe that all lovers should start out as friends. There are also advantages and disadvantages to dating someone you work with, you'll have to do the social math on your own.
The long and short of it is, communicate with her, tell her you care about her, but that you don't want to get involved too soon after her last relationship.
Confront Her about Her Ex
Be frank: if you think she's hung up on, pining for, comparing you to her ex, tell her so, but don't just make stuff up - be prepared to back up what you say with actual evidence. You might suggest slowing down/reverting a bit, that is, going "back" to dating, exploring your common interests and doing all that fun getting-to-know-you stuff, enjoying the chemistry all over again, moving back up to sleeping together...
Be honest, supportive, and communicative, but if you don't find your own needs and feelings being reciprocated, be a man, say so and break it off (this, of course, is one of the complications of working with a significant other - if it doesn't work out, the aftermath can be extremely awkward at best).