I agree with most of these posts. I lost my second son during birth, and the biggest help to me was when people did not forget...even months later. Everyone will be supportive now, but in 6 months? Will they ask about how she's recovering or feeling? Some will, some won't. Some people also find the whole subject of a baby/child dying too uncomfortable to talk about, so they will want to talk about other things. Talking about other things is fine, but not as if a person did not just have tragedy hit that will change them forever.
Also, crying when you heard the news was NOT "not what she needed" - kudos to you for showing you care! A lot of people want to distance themselves, and you did not. Shows you are a good friend.
As for support groups - have her (or you can offer to) check the hospital/OB department or midwife (whoever she was using for check ups) about a group or therapist. They have grief counselors/social workers at hospitals now to help families cope with this kind of loss. We went to ours for over a year. I know where I went they had one-on-one and groups to talk about infant loss. I would have felt completely lost without that.
Finally, just be there. Sounds like you are doing that. And, it's surprising how many people will ask (maybe not immediately but in the next weeks/months) if/when they are trying again. Try not to do that. BUT, if she gets pregnant again, know that a subsequent pregnancy will be absolutely terrifying for her, and acknowledge that.
Good luck. My heart breaks for your friend. And dinner at your place sounds actually nice - not outside the building, but outside her place, where there may be a lot of reminders of what she's lost. Sorry such a long response!