Build me a New Website

I own a landscape company and we're about to branch off and start selling rubber mulch. I have a website already, www.topflightlawns.com, and it works as a communication/landing type deal, we've just never used it to drive traffic or revenue. I didn't know if it would be easier to tap into the existing site and add the mulch or create a new one with just it and some other products but still be under the existing company brand? Hope that makes sense.