Personally, if your running on a 533, best bet would be to put your money into the computer first, it will up your modelling speeds and stuff significantly.

Other than that, auctioning is great.. just you have to be careful. If your just going to buy off of some unknown site then your going to get screwed like you wouldnt imagine.. if you want to auction for your goods 2 great places are ubid.com and ebay.com. Ebay has more of a selection and is more of a p2p kinda thing. Ubid is they buy all refurbished goods from these manufactures for really hella cheap prices and sell it to you for a tad more, in most cases its cheaper than on ebay. Nice thing is that on Ubid you know 95% of the time (if your buying electronics) you will be getting the real deal, and working.. but on ebay sometimes they word things that you have to look out for, or the ammount of sells they have made. On ebay the other person could run off with your money and end up only giving you back up to 200 dollars from the original price (from ebay). I personally buy all my parts now mostly in stores and some things off of ubid, seeing ebay seems to be getting a bit more corrupted every day.

Watch out when your bidding though.. you can get too over excited .. always keep a max price in your head so you dont top it! Dont want to be paying more for an item than it is in stores (seen it alot). :thumbsup:

How much ram can your MB hold? If its maxed then your in a pickle.. buy a new computer for sure. Sounds like you dont have exactly a ton of money though to go out and buy all the new hardware goodies on the market, so i would just suggest investing in maxing out your ram slots. For the renders, stand up, go outside.. and go for a nice blade/bike/skateboard ride or w/e you want.. just do something productive with your time rather then sitting infront of the render screen .

Hope this helped a bit.