There's a really good chart over at Tom's Hardware that will give you a good idea of where your card is. Only thing I'd disagree with is that Tom recommends a card at least three levels higher than you current. while this is a good rule of thumb if you want to know how much a new card is better than your old one it's not the best way of deciding which card to buy. I know its a bit time consuming but work out.
1. Decide how often you are going to replace your card. In my case I wanted something that was going to last and so probqably went above the sweet spot for performance/price.
2. Spend time looking at how much a graphics card cost 1 or 2 years ago. Look at how much the same card costs now. Calculate the devaluation rate. If you're good with money save part of your budget for next year's purchase.
3. Also look at ebay prices for resale value on 1 and 2 year old cards
4. Be careful about power requirements, some of the newer graphics cards have surprisingly low power requirements in many cases lower than an older, slower card. This speaks to thinking how much you'll spend on electricity through the year. Think about how often you play games, some of the faster cards are great but they have quite a high idle power consumption rate.
For an idea of where your card sits the following link list GPU's on a hierarchy chart
http://www.tomshardware.com/reviews/...ew,3107-7.html