hmmm...as i see your config >>
Monitor : Samsung SyncMaster 933
Resolution :1360*768 at 60hz
-- for this resolution a 4850 will be good enough for you,,4870 like card will be an overkill for you.I think ati 5750(1gb ddr5) is the best solution for you.. check this
review
power color 5750 is costing Rs.8100 at theitwares.com. I think its a good deal for you. Power color is a good brand for ati card-relatively new in india.check newegg for buyers feedback for power color branded ati graphics card