20-40 minute video

I have a bride reach out to me saying how unhappy she was with the 10 minute video she received from another company. She said she received the raw footage and wanted to see if I would create a 20-40 minute video using that. I usually specialize in 7-10 minute videos but have also provided longer videos on request. I am just wondering how much I should charge considering I didn't shoot the footage. Normally I ask for $1200 for just a 7-10 minute video. I really have no idea what to charge.