Below is snapshot of the instructions from owners manual for my 05, I think yours would be the same.
On my previous Mercedes, when the OEM light burnt out, I went to local parts store (Kragen) and bought the
Sylvania Silverstar Ultra H7 bulbs, and I was VERY happy with the light output from them. The picture shown in the link above was a pretty close presentation of the improvement I saw. They were a bit pricier, at about $25 each (but had a $10 mail in rebate on the pair), but it was a good price for the quality/improvement.
I acutally liked it enough that now, even though my headlights are still working, I am thinking of switching them anyway.
Hope this helps.