Did you get this fixed - I can coach you through what you ask if need be.
The steps I think you need to take are as follows:
1) Batten down the hatches and make sure there is no direct access to the machine by a hacker. Local crime will prefer to hack a computer by getting direct access to the keyboard if at all possible. It's easier than hacking over the Internet (i.e., a MITM attack). So you need to make sure at a minimum the door is padlocked behind you before you open a root console. If you can install home CCTV and check the footage of you entering and leaving the room before logging into root (crime has the intrusion capabilities of Houdini
it is not without reason Houdini wrote extensively on crime) - a very basic setup can be done using webcams and the Motion package. Secure window shutters if possible (you may not think you need these but you do). A good alarm system can add to internal security. Some TEMPEST shielding if you can afford $1000 (I get the feeling local crime has at least one TEMPEST setup that they move around), but otherwise make sure no clear text passwords are displayed on screen - if setting, e.g., a VPN password on a website xclip and 'read -s' can be used to input autogenerated passphrases/keys etc. without displaying.
2) Encrypt and obfuscate passwords (i.e., don't write them down in clear text). I'm sure you can dream up all sorts of schemes personal to yourself. You need schemes to generate a short password that will only be used to login to a user login (something that can be remembered easily for frequent use), but also schemes to generate the passphrase to encrypt the hard disk which you will only use once in a while etc. You need a scheme as well that will allow you to very quickly reset the password to something new if the need arises (which it does). At one time for example I would open a particular webpage on my mobile 'phone listing English castles, and created passwords noting only the login and # of the castle in the list, using encryption schemes residing largely in my head based on the name of the castle - a scheme that was easy to remember for non crytical/throwaway logins, something more complex for longer passphrases, etc.
3) Lock the X desktop down by creating a public kiosk style setup - run an X window manager but without any menu options that will allow any kind of access to the file system. TWM or openbox are good window managers for doing this. Code xterms to only open after a password has been entered, etc.
4) Setup iptables to open only http and https ports. Connecting to your ISP involves bringing up the network interface, 'ifup [device]' (you may have to set config options for the interface for dhcp); create iptables for connecting to your router in the first instance, and then once the network connection is up connecting to your ISP with only (as a starting point) http and https ports open. Also create a table for when you bring the connection down, blocking all network traffic in either direction.
5) If you have a MITM type hacking problem (SSL certificate errors, data injection), find a VPN, I use ivpn.net OpenVPN servers - all VPNs are not unfortunately created equal, iVPN I personally have found to be about the best (in fact the only one I've tried that prevents most hacks). You will have to add an additional iptable for bringing up the VPN connection. (Note though a VPN only encrypts the Internet connection up to the VPN server, not from the server to the website, and doesn't protect you from compromised websites).
6) Run the browser in a SELinux sandbox - this is an absolute must, I'm still working on a data injection problem even with a VPN.
Install the Fedora security spin packages (there is a post on the forum with a script to do this) and join the forum, read the chapter on security in the RH docs, and make a career of a network engineer - at which point you can provide consultancy services to myself, as being a programmer I do not particularly want to go down this route
MITM attacks are described in the presentation on this page... http://www.thoughtcrime.org/software/sslstrip/
(which doesn't seem to be working at the moment - I'm sure if you google'd it it will be found elsewhere).
If you want to go down the above route post back and we can make a start
The first thing you need to do though you may find is bolt the door of the room behind you, and make sure the windows are secure.