Honestly, I would get a plain yellow gold bangle (or two!), with no markings of any kind to go with it. I think this would make your Cartier one stand out a little and look special rather than "competing" with other designer/decorated ones. Have fun getting your bangles!
I agree - a friend of mine has a love bangle and she wears it with 2 plain thin flat gold bangles, one either side of it and it looks lovely!