Making a powerful IR sender on Arduino basis without driver transistor is easy, see for example this little project: [Link: harctoolbox.org]
Since I have not seen your exact circuit, I can only give some general advice:
* Use proper IR LEDs from premium manufacturers with available data sheets
, for example OSRAM (looks cool with the black housing) or Vishay. Make sure they are 940-950 nm (890 are for IRDA and unsuited).
* Use a proper resistor in series with the LEDs, see [Link: harctoolbox.org]
* Do not EVER connect LEDs in parallel or without a resistor.
* The "constant current" circuit is great if you need constant current despite of widely varying supply current. If you do not have that problem, you do not need that circuit either.
* Not all Arduino(-compatible) boards can provide the same current. ATMega328P (Uno, Nano, etc) can provide up to 40 mA, which is more than enough. More powerful boards much less, just a few mA. Read the data sheet.
OK, that was probably more than you wanted to know...