According to StrategyInformer, JoWood's confirmed an add-on for Gothic 3, to release in the fourth quarter of this year.
Titled Gothic 3 – Forsaken Gods, the update will apparently provide a seamless transition between from the Gothic 3 into Gothic 4, which is expected next year.
The sound you're hearing is millions of Germans screaming with excitement. Gothic and Germany? Coffee and cream.
Update: A very short press release after the link.
Gothic 3 – Forsaken Gods: JoWooD announces official Gothic 3 Add-On
Liezen, Austria, April 14th 2008; JoWooD Productions announces the official Add-On for the award winning roleplaying game Gothic 3. Gothic 3 – Forsaken Gods will answer many open questions and guarantee a seamless step to Gothic 4. Once more you take on the role of the nameless Hero and again you have to raise your sword in anger to save the world of Gothic. On your journey you will meet old friends – but be careful, some old alliances may not have lasted the test of time….
JoWood is working on the expansion and the feedback from fans is extremely important to the developer of Gothic 3 - Forsaken Gods. The game designer and developer are studying the Gothic message boards each day and will incorporate as many of the fan-wishes as possible while working on the extension.
The release of Gothic 3 - Forsaken Gods is planned for Q4 2008. Further information will follow soon!