There are no real easy answers here. Some areas move faster than others and without knowing exactly where you are (which you may not want to post openly for obvious reasons), it would be difficult to give you a realistic expectation of market value and estimate of marketing time.
What others said may hold true to some extent, but aggressively priced homes, properly marketed are moving. While I know some agents will do it, I would not recommend trying to rent and sell at the same time. It puts tenants at an inconvenience which could cause tension in showing. Also, many agents will skip over tenant occupied homes if they can, resulting in less showings, longer time on the market, and it cold negatively effect your bottom line from market stagnation. With a tenant that has a lease that needs to be honored, it would also open you up to low ball offers from investors which could make things seem worse than they are.
If you want, you can contact me through my website (link to my site is in web reference) and I will gladly give you a realistic expectation for your home.