Photo by Olivia Flores AlvarezHouston's doing better than most of the rest of the country economically -- at least that's the consensus among the local talking heads. Hair Balls visited the Heights' 1st Saturday Sale to see if money was indeed changing hands. Grace Hart, of Grace Hart and Company, an antiques store on W. 19th Street, sat down with Hair Balls and talked shop. Hair Balls: How are you keeping the cash register ringing in this economy? Grace Hart: We're going with the flow. If peopl