Changing EIP to the 1st byte of .data section would make windows execute that buffer ? If not, how could I do that ?

code in data section is almost always executed w/o any problems. it's one of the methods of code injection. just make a jmp to code in data section....
you also can set EXECUTABLE flag for data section if code is not executed by default

Please note that you can define ".data" section as:

section '.data' code readable executable

and store real data in other section. Section attributes are important - not the section name.