I guess it is:
'bir evin yanında'
EDIT: I think you could translate 'Evin yanında' to 'Next to a house', but if you want to say it clearly you might add 'bir'.
The '-in' is the genitive case as 'yanında' requires genitive.
Please see the explanations here:
yan = side
yanında = at the side
evin yanında = at the side of the house