To answer your question, use this Yardage Calculator. BUT, before you do, I'd like to offer some unsolicited feedback.
It is VERY possible that you will buy and have installed a perticular style and color that a prospective buyer will NOT want. It's nearly impossible to know what someone else wants. My point is made by looking at the SELECTION of carpeting in the store. (The same can be said for paint.) So, you have to ask yourself, "Am I hurting a potential sale by installing brand, new carpat? Will I get my money back in the sale of my house?" And so on. Carpet replacement is maintenance. It doesn't add any value to the home, new or used. A prospective buyer can say, "I LOVE the house but I hate the carpet. Knock off $3,200 for me to replace the carpet, and I'll buy it." AND, to boot, you knock off the $3,200, lose your 'investment', and the new Homeowner decides to keep the carpet! See what I mean? When you had your home appraised, did the Appraiser 'adjust' the price one way or the other when it came to the carpeting? DO find out because if it's already priced DOWN (to absorbe the cost of the new carpet), you can tell your buyers that the house is, well ..., already priced DOWN to have new carpeting.
IF you're going to replace the carpet anyways, I'd stay neutral. Light blue, baige, tan, and so on. And I'd go with an 'average' Carpet Pile. If you spend too little, you'll look 'cheap' (and maybe the buyers will think you're 'cheap' when it comes to OTHER improvements you've done to the house.) If you spend too much, you'll NEVER get your money back. Again, carpeting is a wear-and-tear item in a house. It's almost expected to have it replaced when a Buyer looks at your house.
NOW, to make matters worst, IF you happen to have hardwood floors under the carpet AND they're in decent shape to be refinished, THEN, I'd definitely do that. Hardwood floors DO add good value to the home ESPECIALLY when they're looking brand new.