Welcome to the Community -
1. In the HQ, we would like to have 2 Storages mirroring with each other, and 3 servers connected there to run VM machines so in case one craches, system doesn't need to start working in DR site. Is it possible, and if yes what we would need to buy (SAN license, special vmware license)
Really this would be a standard vSphere implementation - utilizing vSphere features such as VMware HA and DRS - I would look at one of the Acceleration kits - in terms of mirroring the storage I think would be overkill since most SAN systems are bui;t for resiiency as along as you provide redundancy to the storage network - this doc provides an overview of vSphere licensing - http://www.vmware.com/files/pdf/vsphere_pricing.pdf - in terms of SAN costs will depend on which SAN vendor you go with
2. In the DR site to install 2 servers, and only one storage, and replicate with mirroring storages in HQ. Is this possible, and again ,what licenses we need (for storage, and wmware side).
Likewise you will need to license for vSphere and have to license for SRM at both sites. Once again the licensing on SAN will depend on what SAN you decide to go with - for SRM pricing you can check here http://www.vmware.com/products/site-recovery-manager/buy.html
Even though you have a small environment it is complex enough I would reach out to VMware or a local VMware partner for assistance -