Yes, from your post I assumed you've setup LAN between PC and Amiga successfully.
Private IPs are the ones reserved for internal usage, i.e. on a private LAN (they're not visible from the internet) like
172.16.x.y
192.168.x.y
10.x.y.z
Public IP addresses (those visible to the world) need to be allocated through RIPE to ensure proper routing. Usually your ISP does that for you (you get one of those when you dial an internet connection).
WPA is the protection your wireless LAN needs to stop your neighbors, a hacker driving by, etc. to 'plug' into your network, use your network connection, listen to the data your transmitting (including unencrypted passwords, email, ...).
The older
WEP is still widely used but is obsolete and shouldn't be used since it offers close to zero protection.
If you're using no encryption at all, well... :crazy:
