A REV23 + CardConnect account is required for credit card processing. You can get started here
If you really, really want to keep your existing processor, you can use a REV23 + CardConnect Gateway Only account. However, in this scenario there is a $30/mo fee due to REV23, because CardConnect charges us to use their service. Considering CardConnect will meet or beat any rate you're currently getting, switching is certainly the best option.