You didn't give us much info to go on but here's how I would do it.
Calculate the number of hours per billing cycle that you expect the job to take. Then multiply that by the amount per hour that you want to make. Keep in mind you will have to pay your employees, buy supplies, and pay for all of your overhead out of this amount. An example would go like this:
Job will be billed monthly. 1 month = 4.33 weeks
Job will take 2.5 hours per week to complete
4.33 X 2.5 = 10.825 hours per period.
You want to charge $40 per hour billed
(The amount you charge per hour will depend on what your market will bear. The amount above is just an example)
10.825 X $40 = $433 per month
Any windows, VCT floor work, carpet cleaning, or other special services would be calculated seperately.
Hope this helps. Use this model at your own risk. I'm sure others on here will have their own opinions.