Infected php, can't get into admin.

Saturday, my site stopped working. couldn’t get into admin nor my site. the page just displayed a message like this.

Parse error: syntax error, unexpected $end in /home/content/38/7659338/html/wp-includes/widgets.php on line 212

but not exactly this. I had my tech guy look at it and he found more than 1100 php with some injected code. he removed it and reloaded wordpress. it was up momentary and I could see that not all of my plugins were there. I did have a backup plugin which I ran in april so I was thinking about restoring it. but before I could do that. the site was infected again and now I get this message. My tech guy can’t understand this.
can any one help. I have a screen shot of the infected code if that helps.