If you're having trouble with Google, try "adapter" rather than "converter".
I bought one on Newegg.
More info: I had a hard time finding mine, but it is a Delkin Expresscard 34 CompactFlash adapter. I don't use it much anymore, since most of the time my initial uploading is happening on my MacBook Air. Please note that the limitation on the transfer speed is going to be with the CF card, not the interface - even very fast CF cards aren't likely to tax the limits of, say, USB 2.0 (at least not with my 300x cards).
Don't expect to get anywhere near 3gbps over the ExpressCard interface, in other words.