Mobile development

I need an Android app. I would like it designed and built. Hello, I am a vendor that retail prepaid minutes for gsm networks in my country. The process of selling goes like this: After having an registered gsm SIM card with the supplier, the minutes I purchase wholesale will go into that sim's account. To sell from our registered sim is a process by sending an sms message to the supplier server which will process this information. However my problem is that the sms message is too much characters that is in that string of message. So I wish to create an sms app that will work with the SIM card sms gateway that will be able to already have the string of characters embedded and allow the user to just input the customers Number and amount alone so the process of selling will be more swiftly. The current sms format looks like this : p208 n(number) a(amount) c8900 and we sent to a fixed recipient 6205555 The app we create will have an configuration to set these information and an simple interface for user to sell from. Please contact me if auou need more information