Yes, you can get a reasonable coffee out of a Bar Italia - this was my first machine and started me on my coffee journey originally! The good thing about the BI is that its a boiler machine, so simple and easy to use for those starting out. I really cant remember whether it had a dual walled basket or not, though - someone may be able to help out there. The dual walled basket can sometimes be modified with a Dremel to make it single walled - there is a thread on the site regarding this, but it will be worth it if you can.
Now, to answer your questions...
1. Get a grinder - even if it is a hand held one. Do not get a spice grinder. Its no good getting a bottomless naked portafilter if you cant use beans youve ground yourself fresh and on-demand (coffee goes stale quickly after grinding ie; 3 minutes).
2. Yes, you can get a good crema if you use fresh beans, freshly ground and in a single walled basket. You can source fresh beans from BeanBay or many of the Sponsors. Note - beans from a supermarket are rarely fresh as theyve been potentially shipped from overseas and then sat on a shelf for God knows how long. Roasted beans usually last 3-4 weeks before starting to go stale.
Good luck with the wedding and your new coffee journey! Do what my friends are doing - theyve been together for a while now and are asking for donations to put towards a coffee machine & grinder setup for their wedding presents!