There are three 3G operators broadband operators in Portugal, all of whom offer blackberry service.
Vodafone is probably your best option in terms of service and coverage.. However, you will need to make sure your existing Blackberry is unlocked so that it can take a Vodafone Portugal/TMN/Optimus SIM.
See this link:
As regards, ADSL, I am based in the Western Algarve but to the best of my knowledge there is only one landline operator providing ADSL access into the Almancil/QDL area. This is PT. This would make their SAPO brand the cheapest ADSL access.
Alternatively, depending on the volume of traffic you use, you may find that 3G Broadband HSPDA dongle modem access over the mobile phone network to be an alternative.
The three operators above offer these options. Note Optimus offers such a service under the Kanguru brand.