I created graphics in firefly? express? to use as my brand for my etsy store and I have problems

I think I used firefly to help me come up with a new graphic file(s) that were supposed to work with the following dimensions 1600 x 213, mini banner, and another version that was supposed to be 3360 x 840. Instead I have graphics that I can’t adjust to fit the dimensions. I can’t figure out how to get either firefly or express to create a new version from scratch. I can’t get adjust the scale manually etc to get the graphic to work. Instead I get something that is lacking to be kind. I have attached the original png file that was downloaded from firefly and what it looks like when trying to adjust it to the 1600x213. 

I’m so frustrated and really disappointed. Making banner graphics like this has never been my strong suit and really liked what was originally created. I don’t want to have to use a boring canva banner but I will if I have to.