Can I install a gt 640 1gb ddr5 in my pc?

My PC is a Lenovo Thinkcentre M57 6066
Specs:
Intel Core™ 2 Quad processor 2.40 GHz
4 GB RAM DDR2
Intel Q35 express chipset family
Slots
Slot 1: full length, low profile-height 32-bit PCI 2.3 (5v)
Slot 2: half-length, low profile-height, PCI Express x16
ACPI 280 Watt power supply with manual voltage selection switch
Automatic 50/60 Hz input frequency switching
150 gb hard disk 7200RPM

If there is a better graphics card than the gt 640 and is capable of running in my pc please tell

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