Transferring MP3's to External Memory

I really need some major help. I just bought a Memorex MMP8564 which comes with 512MB of memory, PLUS I bought an external card with 1GB. I was able to transfer 118 songs to the player, but only 30 to the external memory. Am I wrong, or should I be able to get a LOT more onto the 1GB card? I don't even know how I got the 30 on there in the first place, because I couldn't figure out where I was supposed to "click and drag" to. I really need help figuring this out by Tuesday because I want to take this with me on a 14hr road trip!! Also, how would I clear out the player and the card and start all over???? I ask this because I didn't click the button for high-quality transfer, and I'm regretting it because the sound isn't that great.  Any help is GREATLY appreciated!!!