It sounds like your describing the EcoQuest Eagle 5000 Air Purifier, which was the closest description I saw. Here’s their website with a picture, manual, and Dealers link that should be able to tell you where you can order a new one locally or online.

Also, if you do a search on “Eagle 5000 Air” in eBay, you’ll find 2 listings that might be lower in price for you.

Word of warning: My search results also came up with a number of complaint pages that didn’t think too highly of this company. If you do a more comprehensive search, you may turn up more.

Consumer Affairs

Epinions

Regardless, good luck, hope this helps!