I am sorry to tell you that there is no other way but pandora and mms. If you have another friend with a psp1000 he can make his normal battery a pandora battery.
You can make your mms by yourself (as long as it is magic gate supported and < 4Gb). The pandora can be bought in this site or dealextreme.com; they are cheap, like 6-10 US dollars.
About the process, all you need is in this guide: http://www.pspmod.com/forums/softwar...-one-link.html