First download and install this:
LinkThat will allow for console commands to be visible.
Then make a shortcut of the game in your desktop, right click it, go to properties, then at the end of the "Target:"C:\Program Files\Dragon Age\bin_ship\daorigins.exe" add(-enabledeveloperconsole) without the parenthesis, there must be a space b/w the " and the -. so it should look like this:
"C:\Program Files\Dragon Age\bin_ship\daorigins.exe" -enabledeveloperconsole
Then simply launch the game using that shortcut. In the game press the ~ key, and that will launch the command console, you will see a ">" symbol in the top left of the screen. Then type your console command such as "runscript addxp 3000" etc, press enter, and tadaa.
Good luck!
PS for some scripts, the character you wish to upgrade, affect must be selected.