Mapping with the rc car

hi everyone,

i am working on an RC car i modified it i putted in there a bumb sensor and i am planning on putting ir range detector and i will use pic to drive the machine

but the proplem is i want it to go to specficated  area like the first bedroom second bedroom etc and to specficated place like in front of the bed or so.

what should i do for that? drawing a black line in all of the house isnt very good

so what is the best idea to walk around knowing where to go?

i thought about making it walk like 3 second front then 4 second left and then stop but if the battery became low it wont be in the right place ofc so if someone knows the answer please help :)