Kubia
This bit is wrong in your code:-
// I2C device address is 0 1 0 0 A2 A1 A0
#define SENSOR_ADDRESS (0x4 << 3 | 0x0)
It should be
// I2C device address is 0x74
#define SENSOR_ADDRESS 0x74
It's in the data sheet page 10.
Then you need to look at page 18 to define what commands you want to send to it. Here you are better off reading the application note. Page 3 of this note tells you what you have to do in order to read the values.
However, all you code does is request two bytes from the I2C device without setting up any registers.
You need to:-
Sensor digital values can be acquired by writing 01H to CTRL register (address 00H). Read CTRL register. When the value in CTRL register is 00H, sensor digital values are acquired in sensor sample data registers.
Then you need to read the sample registers.
All this assumes that you haven't set up the sensor for offset and span so I don't know how useful the results will be with out this. Again the application notes describe how this should be done.
I am sorry not to be able to give you the code but I do not have one of these sensors (yet).
If it is any help I do plan to use four of these sensors in an up coming project so I will have code available in a month or so.
Just done a web search and come up with this:-
http://jp.makezine.com/blog/AvagoDemo.txt