@Eddy thanks for reaching out; sorry to hear the rainfly is no longer fine. Unfortunately, we do not sell the rainfly separately so here are a few alternate options to consider:

• Contact Rainy Pass to inquire about having a new rainfly made for your Quarter Dome 2. We work with Rainy Pass a lot around gear repair and replacement; they use technical fabrics and know our products well.
• Without knowing what's wrong with your current rainfly, there are a number of products that can help with care and repair, like seam sealers and waterproofing.
• While not ideal from a breathability and fit perspective, a last resort might be a tarp.

Hope one of these options helps!