Did you pay for the commercial to be made originally or hold the rights to it? If not I think it's ridiculous to talk about credit for something you did not create to begin with regardless of what it took to digitise it. How can something be stolen from you that you did not own to begin with? it's not like other people using it is depriving you of any income as you cannot sell it.
I don't know how you are capturing now, but if it's anything USB; that could explain the washed out look. The way to go is with a firewire DAC, but that comes with it's own problems, you also need a frame synchroniser (or TBC) if it's not included in the DAC (most of them don't have it). The best way to improve is to use this firewire DAC and a high end recorder with TBC/DNR built into it (you'll still need a frame synchroniser or separate TBC though). They can be found in thrift stores for no too much money most of the time.
