You can begin here by downloading the latest WHQL drivers/Beta drivers and also the legacy drivers that suit your card type.
List of drivers you need for modding all in one place. Use the links on the right to download the driver you need.
If the links don't give you the proper driver you require then you might have to google the driver version in the list to find the proper legacy version you are looking for.
Guru3D is a good place to find the drivers you need.
Latest WHQL driver : Get the latest WHQL driver >> Official download link
Use with 5xxx. 6xxx, 7xxx, 8xxx GPUs:
AMD Radeon Software Crimson Edition 16.2.1 Beta for Non GCN Products 32bit and 64bit
AMD Catalyst™ Drivers for AMD Radeon™ HD 4000, HD 3000, HD 2000 Series
Use with HD 4000, HD 3000, HD 2000 GPUs:
AMD Catalyst 13.1 WHQL Legacy Driver (Release Date: 1/21/2013) - 32bit & 64bit, use with DirectX 10 cards
Display Driver ver. 184.108.40.206
OpenCL(tm) Driver 10.0.937.2 32bit & 64bit Driver
AMD Catalyst 12.6 WHQL Legacy Driver (Release Date: 7/24/2012) - 32bit 32bit
AMD Catalyst 12.6 WHQL Legacy Driver (Release Date: 7/24/2012) - 64bit, use with DirectX 10 cards 64bit
Use with DirectX 9 cards >> X1xxx to HD 2300
Use these as base files for older GPUs X1xxx to HD 2300 : 32bit & 64bit driver download
After you are done downloading the drivers click here to download FLEM.