Replacing the hard drive is trivial. Just grab a 2.5" ata hard drive and replace the old one. Or get a 44 pin sd or cf adapter and stick a suitable card in.
As for floppies... you can replace the original floppy drive with any drive that you can set the drive select to 0 (instead of 1 which is PC default). It's either a dip switch or you have to manually desolder and solder a resistor on the floppy board.
You can also get one of these thingies too: http://hxc2001.free.fr/floppy_drive_emulator/.
