I need to purchase a software tools for an organization.
the Software package contains following four flows:
1.Mixed Signal RF IC Design Flow
2.ASIC Design Flow
3.FPGA Design Flow
4.PCB Design flow
The software you are looking for is collectively called Electronic Design Automation (EDA) software. The EDA Consortium (www.edac.org) is the industry association that has almost every EDA company as its members. Go to their website and you can get a listing of all the companies.
There are about 300 companies, but 80% of the EDA market is dominated by 4 big companies: Cadence Design, Synopsys, Mentor Graphics and Magma. I would suggest you start by looking at Cadence because they are dominant in analog design and are strong in PCB design. Look at the others too.
There are also smaller companies like Tanner Research that produce university-level EDA tools. They are cheaper but are not used for large design projects.