Access to cash

I am planning to set up a SMSF with my partner.
However my biggest concern is if I require money for a new car, an operation, house renovations etc. can I access some cash??
My super fund will initially consist of cash from interest bearing accounts and shares, all having been previously taxed in my normal income tax return.
Can I access these components.
Later I may choose to roll over other funds from super funds from previous employment
Judy V