Totally depends on what AVG you have. if you have the paid for version then your not to bad. However if it if the free version then security is lacking.
The free version is virus protection only. No firewall .. no spyware protection
CCleaner is a program that does what it says CrapCleaner it removes old files etc from your computer. It provides NO protection what so ever to you computer.
Firewall :- If you don`t have one .. use the xp inbuilt one .. it is rubbish but better than nothing
Spyware protection :- Loads of them free on the net. Some only delete spyware AFTER it has been installed on your computer (eg Adware) some STOP spyware from running on your computer ( eg Spycatcher)
Another good program is Advanced Windows Care :-
http://www.iobit.com/
However running the reg cleaner in this program can delete you uninstall files for various programs. Don`t use it until you have configured it propertly.