General hardware required for Asterisk server

1 am new to asterisk server.

i want to replace my current pbx phone system

current requirements (UK)

lines in 3 isdn 2 = 6 lines
16 anologue internal telephone extensions
6 internal digital lines
and would like to add voip /soft internal phones

could someone please let me know what equipement i need to purchase
to make this work with asterisk server and where from?
does asterisk server run on linux suse 10.1?

thanks for any help

where in UK can purchase ISDN cards and anologue cards?