Add "00" before, and add the first 4 bytes of sha256(sha256("00" + hash160)) after your hash160 (the + is the concatenate operation, not sum)
So you have [ "0065f2a3921afacd998e6c98a5aaa94325ed07ee14" + first4bytesof(sha256(sha256("0065f2a3921afacd998e6c98a5aaa94325ed07ee14"))) ]
The address is just the base58 representation of the hexadecimal number above
Base58 characters: '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
If you really want to do it with a calculator only, there's a sha256 pseudocode here: http://en.wikipedia.org/wiki/SHA-2