how to ask for a raise. updated!

not sure where to post this, but need your advice.

I've worked for the same company for almost 8 years, I'm a medical assistant and do the work of 2-3 people and only get paid $13.75. I work at least 2-3 hours OT weekly to make sure I get all my tasks done. I love my job and I know I'm good at it. but I haven't gotten a raise for the last two years and I just got more work assigned to me and I feel like I need to speak up. I hate confrontation, and I just feel like I shouldn't have to ask since my boss always praises my work and knows that I multitask like crazy to get things done. I feel like I'm just cheap labor and I dont want to leave because like I said, I love my job just feel waaay under paid. minimum wage here is $12. so even tho I'm making more I still feel a little taken advantage of. she told me two weeks ago that the whole office would get paid a little more since we just lost an employee and have to pick up that slack. how can I ask? as a manager/boss what do you expect? and as an employee how do you go about it? I dont want to seem money hungry but I honestly believe I deserve it.

update:

thank you all for your advice I truly appreciate it!! so I asked, i was so nervous and I honestly kept reading these comments to give me that extra push I needed! and to my surprise! my boss told me she had planned to give me a raise and promotion, but was waiting for March to offer me the position! I of course accepted and I'm really excited to start!