You need 3 yards of fabric for the larger cushion plus a yard to make about 13 yards of piping. You need 1 2/3 for the smaller, plus about 2/3 yard to make 7 yards of piping. You can find charts for piping if you do a search for "continuous bias", that is what they cut to make piping. Most of the charts are for quilters so they are calculating based on 45" wide fabric. That means the quantity I've given you for piping is generous because your fabric is 58".

Use the 4" green (high density) foam if this is something that you will sitting on frequently. The 4" is for comfort. If that is not an issue, use the 3" green foam.
Kathy G in MI

Thank you for the measurements!
Where can I buy green foam online?

You can find the green foam at Joann's or try the link below. They have a green foam called Lux foam regular that sounds like what I used.
Kathy G in MI

Here is a link that might be useful: Foam Factory