hmm, how did you come up with the TDA2822 if you know nothing about circuits? I am not sure where to tie the amplifier into the PSP in order to accomplish this, however I can tell you how to figure the amplifier circuit:
http://www.st.com/stonline/products/literature/ds/1462.pdfThat is your specsheet for that chip. If you look at page1 there is an application circuit and that is the circuit(or close to) that you want to build. There are no diodes, just resistors and capacitors. If you are only doing one speaker channel, only use one side of the device.
I believe the 10k resistor size will have an effect on your gain, not sure, that particular spec sheet doesnt elaborate very well.