Dude..... I dun think any rational soul out there will lend a
car to a P plate especially since you just got your license....
Even if you approach an agent they will not lend it to you becos u
r still holding on to a new licence of less than 2 yrs.... But u
can try to ask one of ur frens to rent a car for you..... it is ard
$70-120 per day for normal cars of up to 1600cc depending on the
company you approach.....
anyway in the mean time you should try to improve on ur parking and
turning radius so that you will be comfortable when moving up a
multi storey carpark...... 
Between I am not trying to be mean to you.... just a word of advise
from a more experience driver... 