Database Query of County Code for Zip Code/State Combination

We need a way to pull the County Name and ID based on the Zip Code/State combination someone enters on a form. Here is an example site of what we need: [login to view URL] We actually started working on this project. You can see it on the Zip Code field here: [login to view URL] Unfortunately, some of the requirements changed and the programmer was no longer available. I've uploaded 2 files (one with two formats). Ultimately what we need is the "CountyID" field out of the [login to view URL], and the Count Name from either. Someone will enter a Zip code and State, then we must go through the ZipList-County-and-Zip-Codes file to see if that ZipCode/State combination has more than 1 County residing there. If it does, we must display the available Counties, let them choose which one is theirs, and then go to the [login to view URL] file to get the CountyID associated with that County Name and State combination. If the ZipCode/State combination only has 1 County residing there, we do not need to do the second part of the process. All we need to do is default the CountyID = Zero and our quoting software can handle it just fine. However, we do need the final County Name (either from the first part where there is only 1 County, or from the second part of the process where they would select their County) so we can pass that into our CRM.