Twitter & Facebook publicize frustration

Hello everyone,

I am using managed WordPress via GoDaddy to run my blog. I have it set up so that when I write a post, WordPress will publicize to Twitter and Facebook. However, I would like to tweak how the Tweet and the Facebook post look. The current status for each:

– Twitter: Posts the link and whatever I put in the details box in the publication area of the post.

– Facebook: Posts the title, whatever is in the details box, and then the first few lines of the post and a picture, which seems to come off the Instagram slider widget I have on the site.

Here is how I would like the Tweet and Post to look:

– Twitter: Tweets the link, whatever I type in the details box, and the featured image
– Facebook: I want it to look just like it does now, except the post uses the featured image rather than some random image from my Instagram slider.

Does anyone have any ideas of how I can go about doing this? I tried to figure it out on my own by Googling it, but I don’t seem to be getting anywhere. Also, I am also very technically ignorant — I can’t write code or anything. I am hoping there is a plugin or something that I can use. Any thoughts/advice/etc would be greatly appreciated!