I think a lot of the time people tend to put too much emphasis on the actual items we use in our rituals and not the ritual itself. When I first started wanting to use Greater Magic and perform my own rituals I was hesitant to perform anything at first until I had the "perfect" robe, the "right" chalice etc as described in The Satanic Bible. I somehow hadn't read the book properly, didn't understand the overall purpose of GM and ended up believing my magic wouldn't "work". For many people most of these things are not easily obtainable/costly. If you are eager to perform a ritual then use whatever you can find to achieve your basic setup. Currently I use a black table from a cheap shop as an altar, I have taken an old hooded gown and dyed it black with fabric dye, and for my sigil of Baphomet I drew the basic design onto some thick A3 cartridge paper and painted it.
For me these items are much more "magical" as I had to use some creativity in fashioning a ritual chamber from everyday items. I believe the fact I have had to channel energy into making them has aided me in much more successful workings. I'm sure after much thought you will find a way to make these items yourself without the help or advice of others. If you are skilled in arts the round table for the sigil sounds good, but I wouldn't know where to start on making an altar.

Hope this helps.