hello Sheri, Dont feel bad about being clueless at this stage, there are lots of decisions to be made in order to find out the cost of an addition....
your wishes turned into plans
plans to permits
existing building structure transitions to new addition
the actual building of the addition
(rough framing, hvac, electrical*, plumbing, insulation, roof system, drywall windows and doors)
the interior ( lighting, paint, flooring, cabinets, appliances, etc)
*electrical needs to be assesed to see if there are additional needs
so all in all trying to give you a ball park is very difficult without being onsite and discussing the project more.
you are welcome to email me and set an appointment at: email@example.com
Property Maintenance Gen. Contrs