In the film Veronika Decides to Die, Sarah Michelle Gellar appears to be wearing a lantern sleeve cardigan by Vince. It seems fitting for the main character to wear designer apparel while trying to over dose on pills. No one wants to be found lying in their own vomit while wearing a sweatsuit from the clearance rack at Walmart. Nobody!
The details of the cardigan see to all match up. Also, the sweater was sold in stores around 2007, which fits with the timeline of the production of the film since it wasn't released until 2009.
It's hard to get a really good look at the sweater in the film, but from the shots I've seen, it looks like Vince.