Sorry to hear your collection was lost. I also live in CO and actually not far from where it happened. I frequent that Costco for my family's need and truly love that community.
Probably as others have already mentioned, if you are on a budget, rebuild your collection could be a long time journey especially if there were old rare sets in your collection. Aside from those big retailers, you can also go to BrickLink and BrickOwl searching for what you want.
I am running a small BrickLink & ebay store, but don't have super old stuffs. If you are interested, welcome to take a look.