Try the following restaurants (in the order of appearance):
Posthorn, Zürcherstrasse 164, ☎ 056/4062712. all week 11h-14h,18h-24h. : was called 'Tra la Gente' for some time. It's a recently renovated Italian place with quality food in a classy atmosphere. I don't know if they've already given it a name, but it's near the catholic church on the opposite side of the nearby roundabout. above average. edit
Kloster Wettingen. : the monastery is some 10 minutes walking from Neuenhof across the Limat. It also houses a restaurant, in fact it's the oldest one in Switzerland. Classy quality food, nice rustical setting and a nice selection of wines. Bit on the high-end regarding budget and a very popular destination at times. edit
Rüssler. : an old-style Swiss restaurant up the Rüssler hill. This is a favourable destination if you want to combine a solid meal with a nice stroll/hike - they're near a junction of hiking paths. edit
Berner, Zürcherstr. 82. : has fairly standard Swiss food garden seating for the summer. Tried it and liked it, but expect no thrills. edit
Landhaus, Zürcherstr. 128a. : again an old-style Swiss restaurant, though it's led by a Finnish lady. Plain but good quality food - bring your appetite because portions are massive (in particular the 'Garettli' ;-). Please note: these guys aren't open on Saturday evening and the whole of Sunday. edit
Er + Sie, Zürcherstr. 137. : a bit of a drag. Standard pizzas & pasta, cantine ambiente and a confused waitress - kinda italian ;-) edit
The 'Landhaus' restaurant also has a few hotel rooms; never entered it, but if they're anything like the restaurant then expect basic Swiss standard at something like Sfr.100 per room per night.
Else the Kloster Wettingen has rooms. It's just across from the bridge on the other side of the Limmat, so for the pleasant 10 minutes walk from Neuenhof you get a picturesque, pleasant and quiet place to stay over. Plus their restaurant is better.
Anything else, you're better off staying private or go to Baden.