Bill's getting a new car that's capital (5)
I believe the answer is:
accra
'that's capital' is the definition.
(capital of Ghana)
'bill's getting a new car' is the wordplay.
'bill' becomes 'ac' (short for account).
'getting' is a charade indicator (letters next to each other).
'a new' is an anagram indicator.
'car' anagrammed gives 'cra'.
'ac'+'cra'='ACCRA'
(Other definitions for accra that I've seen before include "Main city of Ghana" , "foreign capital" , "Ghanaian city" , "Largest city of Ghana" , "West Africa capital" .)