I reuse laptop or cell phone charger power supplies - have tons of the laying around. You can also ruse an atx power supply.
The arduino itself doesn't consume much current (on the order of ma). So pretty much anything will do. You will need to figure out your future peripherals and how much they consume.
In order to get 3.6V and 2.2V i will use some kind of regulator or another 2 different power supplies ?
You can but that requires some low value resistors so it may not be terribly efficient.