I've got the Terralux 220 as well. I like the light but like you I somwtimes wish I had a little more light. I've added a B&M Lumotec IQ Cyo R Senso Plus dynamo powered headlight, a taillight, and components for me to build a new front wheel with a dynonub to my Amazon wishlist. Terraluxes are cheaper, but I love the idea of dynamo lights. According to online reviews the dynamo powered light I have in mind is as bright as a Magic Shine and requires no batteries which will be a huge plus. Now if only Santa is REALLY generous... (it's not a cheap proposition plus I already have studded tires and clipless pedals and shoes on the list as well...)

In the meantime for me, a second Terralux might be a good idea. If you try it, keep me posted on how effective a solution it is. Good luck!