Why don't you try the Ibis Goteborg city hotel which is located at the seaside and very close to the metro and railway station, the Svenska Massan Exhibition Centre and the convention centre. The other option is hotel Allén, which is located in the center of town and only few minutes for entertainment and shopping. The Exhibition Centre and the amusement park Liseberg is also just minutes walk away. Also
Goteborg hotels page also has more information on Goteborg accommodation, so just have a look and make your booking.
I heard from my Swedish friend that the largest garden exhibition of northern Europe held in
Goteborg from 28 June to 28 September, and it takes place at the most popular gardens of Goteborg. I am very excited to visit this as it is one of the popular
events of Sweden but never get a chance, maybe I'll try in this September.
In Goteborg, there is always something happens and many
things to do and see including museum, music show, Opera visit and much much more.. so be lucky to visit one of them!