Well, if you don't want to use sql command bench you can stop Alfresco, and then copy its entire folder.
Just make sure, that in your Alfresco directory there is a folder called mysql, which should be there,
since you're using 3.3. That is, if you're using MySQL and not another database.
When Alfresco is stopped, and no sql process is running (verify simply with task manager), then you're
Alfresco folder includes you're complete database.
If you can, you could copy that folder to another server and test the upgrade there, that is the safest way.
Therewith you make sure, that your backup is working and if something goes wrong, you've got
your untouched original server.
Anyway, to upgrade, you have to install Alfresco 3.4 in an empty folder (so leave your backup somewhere else
for the moment). Start it to make sure, that it works.
Then stop Alfresco 3.4. Delete the mysql folder of 3.4 and copy the mysql folder of your 3.3 backup in its place.
The same goes for the alf_data folder of your 3.4 install - delete and put backup in place.
Start up Alfresco 3.4 again and watch the alfresco.log file for what it tells you.