What transistor are you using? I can't see the second letter/digit in the picture.
You will want to pick the right value of base resistor so you fully saturate the transistor. If you don't, you risk generating heat. Shouldn't be a problem for you at such small currents, but it is easy to work out the correct value for R given the hFE value of the transistor.
If you want to try working it out, check equation 4 under "Choosing a suitable transistor" here:
Transistor Circuits
If not, post the model number or hFE or datasheet and I'll try and help (with the disclaimer that I only learnt it from ericgibbs a few days ago!).