Hello,
This seems like a very straight forward project, although you've provided no details about the sensor data serial stream, so it's hard to estimate what effort is involved in interpreting that sensor data stream.
I have several Arduino boards, and a couple of Ethernet shields based on the Wiznet 5100 chip, here on my bench already. I don't have an RS232 board, but I can probably simulate your RS232 sensor input using a 2nd Arduino connected via TTL signalling.
I should have plenty of time available to tackle this project with you over the next 7 days.
I look forward to working with you.
Anthony May
Techydude Consulting
Sydney Australia