Good Diffie Hellman Encryption Method
What would be the best encryption method[...]?


The standard approach is quite simple. You have a Diffie-Hellman shared secret $K$. Because $K$ is not actually uniformly distributed you run $K$ through a key-based key derivation function (KBKDF) like HKDF (or even a "simple" hash), this is your key $k$ then. Then you use $k$ to symmetrically encrypt (and authenticate) data using a unique nonce for each data packet. You can also derive multiple different keys from the shared secret, e.g. one for each transmission direction.

You may want to note though that your current parameters are a bit on the insecure side being only 12-bit long as opposed to the current standard 2048-bit length.