M Parc at Dreispitz has a OBI hardware shop. I kind of live in there and know where EVERYTHING is. Tram 10 goes through the city and to MPark station.
The drill you want is a Bosch. A cordless screw driver called IXO. 3.6 Volts if you are not doing a lot of work in one go and a 7.2 Volt of you are going to spend a lot of time in one go (hours).
Go for the basic version and then on the same aisle (row) you will find little kits containing all the attachments you will ever need (near the end of the aisle on the checkout side). You can even find drill bit attachments to clip onto the IXO. I say clip on because the attachments are a hex type version. In stead of taking say 10 plus seconds to attach a new attachment (the old way) you can do it with the IXO in about a second. I think the attachment system is magnetic. Very quick and easy too. I have the Lithium Ion model released before the IXO and the system works very well and I can drill holes through wood easily too. The drill has torque settings so you won't apply too much torque and wreck the job.
The next step up is the cordless drill/drivers. But judging on what you have stated this is an over kill and they are heavier too which can be tiresome when handling the drill for long periods. But there is one on special at the moment next to the checkouts.