Seats wise, you have plenty of options open to you: first question is do you want to keep your rear seats? If not, that gives you loads of options for sports seats and harnesses, plus you could put in a rollcage for a great motorsports look.
Otherwise you're looking at a retrim (pricey, but you can have anything you want, pretty much), or seats and doorcards from a nicer model 206, like the GTi or GTi 180. Full leather seats are rare (I've been after some for donkeys but when they come up they're always out of my price range), and if you're not afraid of taking on some fabrication work you can even look into getting some from a 206CC - it's apparently quite difficult getting the rears installed though but they look mint when they're in. Ebay's your best bet for these, but there is a 206-specific forum which isn't as nice a place as Torque Cars but is ok for buying second hand bits.
As for getting hold of a bodykit, if there are no suppliers near you then you will need to research some bodyshops, ring them up and ask if they can supply and fit one for you, show you some examples of other cars they've done then pick a kit somewhere like Peugeot Ecosse and have them ship it to your bodyshop so they can fit it for you.
There're all manner of bodykits available for the 206 from full on wide arch chav kits to subtle tweaks and motorsport flavours, so do some Googling and see if there's anything you like.