Optima battery nowhere to be found??

As some know, I have a 92 LX. I have a small sound system. 1 12" 1000 watt peak Pioneer sub with 1000 watt amp. I constantly get dimming of my lights when I play my music fairly loud. My Pep boys Pro Start battery only lasted me almost 2 years. Now it dies with only having my headlights on for about 15 min. Everyone tells me that my sound system is a good reason why my battery is dying. They all tell me to buy a yellow top optima rather than buying a CAP. I have the money now...

I CANNOT find this battery anywhere.. calling tons of places, they tell me they can order one directly from optima and will be here in about 4 days. Others tell me "for some reason we haven't had them in forever." I kinda want one today so I kept calling around. Interstate batteries told me they stopped making my type of battery (YEL51R) about 16 months ago because they are redesigning it? They also said that if I DO find one, it will be a pretty old one.. They don't know a time frame of a new release. Anyone know ANYTHING about the YEL51R? Pleaseee??? I'm about to just go buy a CAP untill then I guess... running my car in its current condition will only kill my battery more and alternator as well. Any ideas?

Thanks!
Richard