First, you should link in a reference to the Hata and Ericsson models. I haven't heard of them, and a quick search on Google didn't give anything.
Path loss and received signal strength are typically calculated using the Friis Transmission Equation.
To use this equation you must know the distance between the antennas, frequency, the gain of both the transmitter and receiver antennas, and the transmitter power. Then you can calculate the received signal strength.
Then you asked about the SNR (signal to noise ratio). In order to calculate the noise power, you have to know the bandwidth of the receiver. The noise power at the receiver can be calculated as kTB, where k is the Boltzman's constant, B is the receiver's bandwidth in Hz, and T is the temperature in degrees Kelvin.
A simplified version of this is simply -174 dBm + 10*log(B)
The -174 dBm is kTb at room temperature in 1 Hz of bandwidth.
You also asked about calculating interference. In general this cannot be calculated. If you are expecting in band interference, it must be measured at the receiver site. Since all countries tightly regulate electrical emissions, and if you are operating in a controlled band (controlled by the FCC or similar agency), then your inband interference should be minimal. If you are operaing on one of the ISM bands, then you have to expect almost anything in terms of interference.
Lastly, you asked about throughput. I am guessing that you mean throughput in terms of bits per second. This is a system level question that I can't possibly answer. It depends entirely on the bandwidth available, and parameters such as modulation type, and the SNR requirements for the receiver.