as george says, contact your nearest glazier and get it cut. 4 holes drilled 10mm diameter… come in and down a min of 25-30 mill from each corner…
you will need a laminate glass or toughend glass… so best ask.
you also want the glass to have a polished edge or they will leave it raw cut which will have a very sharp edge. at very least you want an ariste edge, but best asking for polished.
stand off fixings can be bought from http://www.ispitrade.com they offer a good budget polished aluminum stand off for about £1 each but must be bought in box of 20 or so, but you will find thats as cheap as you will get them ide think.
alternatively you could go for a trade supplier to cut it all in polished edge acrylic…