what to do?

[Tomas]

Go for the a1200 tower. It has more chip ram and a better gfx chip, which will help alot with os3.9. The hardware upgrades for the a1200 is both easier to find and cheaper afaik.

Welcome to amiga.org

[Tomas]

You should get a accelerator with ram and a 68030 or higher. A cdrom drive would also make things much easier.
And the 3.1 rom set.
But it all depends on what you want to use the machine for besides running OS3.9.

[Tomas]

can i add a dvdrom without problems? or do i need a card for it?

Should work just fine with the right drivers. But i strongly recommend that you atleast get the 4way ide buffered device.
I bought this one: http://buy.elbox.com/cgibin/shop?info=510EX4&sid=428ae63d
Which both enabled me to hook up both a dvdrom and a standard 3.5 inch hard drive. It came with floppy disk with drivers that supported dvdroms even with long filenames.