PHP API Interface

Hi I have a php database which contains company information and is referenced to an IP address, what i am looking for is somebody who can build me an API system that i can give to people wishing to access my database and references ip addresses. the api will only use the Ip adddress as the sole lookup variable, and will return a set number of records from the search as an xml feed. The api will need to have a unique key and id number to access the records (which will be different for each user) and so will need to have a database to check this information against before referencing the data, or however an api works. I also want to be able to limit how many look ups a particlular api can look up a day. so for example i might want to allow 100 free lookups a day but but then set different levels for paying customers. Thanks For viewing the project