No way that box has a 53 MB HD. My first Quadra 605 had 256 MB. It must be a 60 GB Drive, right?
That machine also used PC100 RAM DIMMS. Good luck finding those. You can use PC133 in a pinch, but they'll both be pricey if bought new. You have four DIMM slots and can put 256 MB in each for a max of 1 GB RAM.
Also, if you upgrade the HD, don't buy larger than 128 GB.