Log into the database as an administrator through postgre Admin III and backup your database from there. You can store this backup in any folder on your system and copy to any location of your choice later on (USB stick included). If your database is a big one you might need to use an external hard-drive to move to another system if required. To restore the same database simply create a blank database with a name and restore your back-up on this new database you have created. All these will be done from postgresAdminIII. That is if your web-client is not doing the backup. Hope this would help you. You will have to make sure you have all the same modules loaded on the system you are transferring too so that all functionality work as in your original one.

When you are logged into pgAdminIII as an administrator, locate "Databases(number of databases inside)" right click and select New Database. In the pop-up window, under "Properties" tab give a name for your database in Name field, in Owner field select openpg, Encoding field select UFT8, in Tablespace field select pg_default. Leave everything else as they are then click OK. Right click on the newly created database, which should be empty and select restore. In the pop-up window, select the file which you saved as a backup (see first paragraph on back-up), click OK and that should be it. When you log into the webclient you will see the new database and the log-in details will same as the original back-up database

I think i was trying to do that, but backup with PgAdmin III has sooooo many options.... I have done it before but restore didnt work :( maybe i haven't set proper options... To backup i have to set options within 5 tabs in dialog window... it is too many for me to figure it out...