Hi,
A 3.3V voltage regulator is one of the most simple, most common and cheap devices. I can´t believe that there´s no such thing around you.
Open any defective electronic device and disassemble one. I have a lot of electronic parts around.. I´m sure there is a voltage regulator ...
I think that it doesn't provide sufficient current
You need to know the current comsumption. Independent if you use a ready to buy suppl, use a voltage regulator or design one on your own.
You need to find out from datasheet or measure it.
For any work with electronics you need a voltmeter and an amperemeter.
The given circuit won´t work, because the outout voltage is not stable.. it is too weak.
If you want to build one on your own, then you need some kind of voltage as reference. Maybe a zener, or even a LED may work.
Then you have an OPAMP, a FET or a BJT and some resistors and capacitors. With this parts you can build some kind of power supply.
Klaus