Hi Otley,
Way to go on making the leap into starting yourself.
From my experiences at the start I spent what was a fair amount of money for me at the time on wasted marketing. Certain things are fairly essential I guess to build a brand but don't expect signs and car logos etc to bring in floods of people.
If you've got plenty of time during the days just now to fill get your company on Facebook, twitter and linked in which are all free. Get all your friends to like the pages etc and some of their friends will do it and the snowball effect will begin. You can then regularly update these about how the business is coming on and let people see offers and deals.
There are plenty of things you can do throwing money at it but your time just now will I assume be around 80-90% marketing and 10-20% being a physio which is the opposite of what we want but Facebook etc is free and it may just lead to the friends friends friend getting injured and mentioning 'I heard of this clinic.....' and the ratio of working as a physio will change slowly but surely.