Check out the H11 to H9 conversions. 2 Tabs to cut, one plastic @ the connector and one metal @ the bulb's base. You would be going from 55w to 65w and about 1350 lumen to 2100 lumen. The fiesta's headlights have a shield for the bulb so it "should" be fine.
Edit: The bulb runs "harder" so life would be shorter...
Edit2: Not my vid. but here's a clip of what I'm talking about. You could also use hand tools as per other guides.
[video=youtube;_mrbdQmck7E]https://www.youtube.com/watch?v=_mrbdQmck7E[/video]