hi im planning on fitting a turbo to my b200 engined Volvo 360 but am unsure were to get a oil feed for the turbo from

You can drill into the oil gallery where the turbo engines get their oil from, not recommended because you get metal flakes in your oil lines.

Better options are the oilpressure sensor hole, use a 'T' piece! or the blanking bolt/thing under the waterpump on the front of the engine. Both have 1/8 npt thread if I remember correct