yes, u can use an NPN transistor to "boost" the power, thouhg what type will be up to your research. a 2n3904 is a simple one. you hook the (B)base to the output of the 555 (pin 3?) and the (E)emmiter to ground, then connect the led to your powersource, with a resistor to limit the 5V down to 1.9 or what voltage u want, and connect that, to the (C)collector. then it should work all good... otherwise if want to use a higher frequency, you will probably need to use a mofset and connect it the same idea, but with the gate connected to the output of the 555... ask somone else though about that as iv dont rember how.