The cash flow is really slim on this deal. You really shouldn't accept anything less than $100/mo. This is a townhome, right?
If you have questions about what the property could be rented for you should ask your realtor to send you rental comps for similar properties that have been rented within the past 3-6 months.
A 20% downpayment is pretty significant chunk of cash. For your first deal it might make more sense to minimize the cash you put into the property so you have adequate reserves and more money to invest in future deals too.