aquafuzz , the most basic thing you can do is theming your player.
First you'll need to extract your current firmware. The guide is
Here.
Keep a backup of it in case you need it in future. You might also want to upload it to the forum so that others trying to recover their players are able to use it, upload link is
Here.
Next, you need to modify the firmware to your liking. The guide is
Here.
There are many themes available in the downloads section, basically just insert the images individually into your own firmware. Some might fit your player some might not due to the difference in layouts, and you might need to do some manual editting.
Finally when done, flash your edited firmware back into the player. The guide is
Here.
Take note to always use your own firmware for editing, never use someone else's firmware or you will risk killing your player.
Lastly regarding the memory, i've checked the samsung datasheet and it is a 512MB memory chip. You might want to consider a refund of sorts since you paid for a 4GB player.