Arduino + rfid + accuracy + gprs + xively

Hi all, I need a programmer to help with a data logging solution using rfid (reading a mountain bike riders unique rfid wristband) and allocating highly accurate times for mountain bike racing. The data is then stored on the ardunio sd card, and also uploaded to xively via gprs. If no gprs signal available, the ardunio will be collected to retrieve the data. I will then use xively to use the data and incorporate into excel where the rfid wristband has been allocated to a particular rider. I am happy to use the programmers recommended hardware, where reliability is paramount. The mountain bike race format is called enduro, where this is a start gate and finish gate for each stage. I would be looking at creating 6 stages, so there would be 6 start gates plus 6 finish gates. The finish gates may incorporate a larger rfid antenna (later) to increase range to 3metres, but I dont see any change with the programming, other than identifying each module with a unique name, so xively knows where the data has come from. So I believe the hardware needs to incorporate: 1) ardunio 2) rfid reader (currently using the rdm600 but alternative is fine) 3) gprs (currently testing sim900 for australia) 4) perhaps additional time clock for accuracy I already have 200 wristbands so would like to use what I have. They are 125khz Em4100. I can skype to discuss further if required. Regards, Steve