The below map shows an aerial view of Santa Eulalia highlighting the location of the Congress Centre and the Tropic Garden Hotel. Complete addresses are:

Palacio de Congresos de Ibiza (Congress Centre)
Av. Dr. Camacho s/n
07840 Santa Eulalia del Rio
Ibiza

Aparthotel Tropic Garden
Carrer Pare Vicent Costa nº10 (Urbanització Ca's Capità)
7840 - Santa Eulària d´es Riu 
Ibiza

To view a map of Santa Eulalia on multimap: http://www.multimap.com/maps/?hloc=GB|ibiza#map=38.985,1.53117|16|4&loc=ES:38.90886:1.43238:14|ibiza|Ibiza,%20Baleares