DHT sensors with RGB LED
So far I only get 1's and 0's      


Before moving into the LED parts, you have to make sure that your system can correctly read the DHT sensor. There are debugging example from arduino-info.wikispaces.com     


  How can I change these integer values to output string say RED, GREEN or BLUE? 


You can do it by simple if-else statement. This would be better than your original code, because there are multiple if's without any else which is (although not so significant) less optimal.

So, if put together, you can try:

void loop()
{
  int t,h,chk = DHT.read11(DHT11_PIN);

  switch (chk)
  {
    case DHTLIB_OK:  
                Serial.print("OK,\t"); 
                break;
    case DHTLIB_ERROR_CHECKSUM: 
                Serial.print("Checksum error,\t"); 
                break;
    case DHTLIB_ERROR_TIMEOUT: 
                Serial.print("Time out error,\t"); 
                break;
    case DHTLIB_ERROR_CONNECT:
        Serial.print("Connect error,\t");
        break;
    case DHTLIB_ERROR_ACK_L:
        Serial.print("Ack Low error,\t");
        break;
    case DHTLIB_ERROR_ACK_H:
        Serial.print("Ack High error,\t");
        break;
    default: 
                Serial.print("Unknown error,\t"); 
                break;
  }
  //moving on into next parts only if you get "OK" from serial reply, which means you successfully read the DHT11
  t = DHT.temperature;
  h = DHT.humidity;
  Serial.print(DHT.humidity, 1);
  Serial.print(",\t");
  Serial.println(DHT.temperature, 1);

  //----end of sensor reading and debugging

  if (t&lt;=17)
  { //blue
   digitalWrite(bluPin, HIGH);   
   digitalWrite(grnPin, LOW);  
   digitalWrite(redPin, LOW);     
   delay(100);
  } else
      if (t&lt;20)
      {
       digitalWrite(grnPin, HIGH);  // aqua  
       digitalWrite(bluPin, HIGH);  
       digitalWrite(redPin, LOW);  
       delay(100); 
      } else
      if (t&lt;23)
      {
        //....  
      }
      //....
      //and goes on

 delay(1000);     
}


And yes, as @Matt suggest, it would be better if you use PWM to control the RGB led which will give you (mathematically) 255*255*255 colour possibilities instead of 8 combinations from digitalWrite(). For example:

//....
//....
  if (t&lt;20)
  { //aqua
   new_t = map(t,DHT11_min_temperature_reading,DHT11_max_temperature_reading,0,255);
   //you can do self research about DHT11 maximum and minimum temperature reading
   //parameters 0 and 255 is the minimum value of PWM(0) and the maximum value(255)
   AnalogWrite(bluPWMPin, new_t);   
   AnalogWrite(grnPWMPin, 255-new_t);  
   AnalogWrite(redPWMPin, 0);     
   delay(100);
  }
//....
//....


Hope it helps :D