1st DX Xenon light, help needed

[hyperloop]

Hi all, the only xenon lights i ever owned were the usual stock M@g AA and 3D, then i got into LEDs, but we'll just leave that aside for now.

So i ordered this

http://www.dealextreme.com/details.dx/sku.2525

and this

http://www.dealextreme.com/details.dx/sku.3048

and this

http://www.dealextreme.com/details.dx/sku.8683

so here's what happened, got the light, slipped in some CR123 primaries that i had and turned it on, beam was NOT very impressive so i decided to switch to RCRs and i slipped in the charged RCR123s and

So i took out the replacement bulbs i ordered and lo and behold, they were bigger than the original that was in the light. The replacement could fit in, but it was so big that when i turned on the light, there was a HUGE doughnut in the beam.

Am in no way a technically inclined person, no modding skills whatsoever, i quake in fear at even the thought of changing a clicky switch in the tailcap, haha. So i need some help here:-

1. What replacement bulb should i get that a protected 3.6v RCR123 will not fry?

2. Are there any simple and i mean simple bordering on idiot proof things that i could do to this light? I'm prepared to TRY to change the workings of the tailcap from a twisty with momentary on into a reverse/forward clicky (prefer forward) based on advice from you guys and maybe get a drop in module of some sort.

Thanks a lot in advance