cannot be used to protect a physical product (except software code, semiconductor masks, architectural drawings and ship hull designs).
cannot be used to protect an already published utility, nonfunctional design, or process.
Your facts suggest that neither copyright nor patent protection will offer any protection.
can only be used to protect a particular product, to the extent that others attempt to suggest that their version of the product is actually that of the trademark owner. Example:
Sony manufacturers an HDTV. The TV is the product of many different individual elements, some may be patented or copyright protected -- others not. The HDTV concept itself cannot be protected -- anyone can build and market one. But, only Sony can build and market an HDTV that actually displays the Sony trademark -- and only Sony's HDTV can contain Sony patented and/or copyright protected elements.
The point here is that assuming that your ability to protect a marketing idea for an existing product requires a combination of (1) obtaining a license from the manufacturer for any portion of the existing product that can be protected via copyright or patent; and (2) marketing the remainder of the product with your trademark, rather than the manufacturer's, but only after obtaining a license to market. The reason for #1 is obvious. The reason for #2 is that where an existing product is functionally identical to a preexisting product marketed under an existing trademark, the original manufacturer can argue that your product is diluting the original manufacturer's good will -- even if you do not use the manufacturer's trademark.
BotXXXXX XXXXXne, if you want to be able to utilize your idea in any substantive manner, you will almost certainly need a license from the original manufacturer. Once you have this, you can protect your idea against others who may attempt to usurp your new use.
Please let me know if I can clarify or assist you further.