This website
https://www.wintercreekcloth.com/A-P...t_p_10405.html shows the border as being 10 inches wide with a 4 repeat across the fabric and it looks like they have all the fabric.
This website
http://www.thequiltcorner.biz/shop/c...2074%E2%80%9D. says the finished quilt size is 74x74 and has a kit to make the quilt.
Edited to add: Because the corners have to be mitered on the curve of the green, I would verify what they say you need and add about an extra 12 inches to it. If you only had to miter and didn't have to match the pattern, it would be a bit simpler.
Based on the finished being 74x74, that is slightly more than 2 yards long and there are 4 sides and 4 repeats across the fabric, so you will probably need about 2 1/2 yards to make sure you can miter the corners. Email wherever you bought the pattern from and ask them.