I have 24 red 3mm LEDS in parallel. Tried running them with 9v battery. Only 5 could get powered. What do you suggest I do to have all of them running?
I figured. I calculated and apparently my circuit needs 450mA of current. Is there some sort of current amplification circuit I could build?
Each LED needs its own [u]current limiting resistor[/u]. If you calculate and select a resistor for 10mA each that's a total of 240mA and your 9V battery should last a couple of hours.
I figured. I calculated and apparently my circuit needs 450mA of current
You're probably getting more current than that. (The with no current-limiting resistor, current depends on the internal resistance of the battery.)
I was thinking of a circuit more like this one:
Hi,
OPs diagram
Yes, a series circuit would make more sense, however you had better calculate your supply voltage before committing to it.
Tom.... 
PS Your original circuit, looks like its series, note parallel.