Yeah right..
Aren't they meant to teach you those things during your PPL course?
I was an instructor once upon a time and you didn't pass your skill test until you could demonstrate proficiency in all of those areas.
Get out there on your own and go and expand on what you have already learnt. Do not follow a line on the GPS, dead reckon. Read up on the methods of radio navigation, buy a book called VOR/ADF & RMI by Martin Cass. Buy a VORTRAC stick it on your chart and practice position fixing etc. This will help build up your spare capacity. Forget the Archer, fly something cheap, they are all the same at the end of the day, you have 50hrs remember, dont be a hero.
Get used to doing the performance calculations for every flight, this will make you familiar with the techniques you need to use during your CPL training. Get familiar with planning and and providing accurate ETA's. This list goes on, unless you are under confident forget this structured rip off. Thats all it is.