You can use your Arduino Uno R3 as an ordinary ISP programer for your atmega328p chips. You can write them with any kind of code, including a bootloader if you really need it.see this tutorial: http://pdp11.byethost12.com/AVR/ArduinoAsProgrammer.htm
If you had read his postings you would have seen that this is exactly what he was trying to do.
What version of the Arduino IDE (Adruino Program) are you running? Version 022, 023 work fine, Version 1.0 has a problem and version 1.01 should work. My best experience was with 022.The resistor needs to be connected on the Arduino Board, not on the chip to be programmed. 120 - 150 Ohms to +5V and reset.
Sorry, I'm french and I've some difficulties to speak correctly english so ...