Adelmo's is a cozy little Italian spot a couple of exits down the highway from you. Maybe a tad higher than your range, but only by a few bucks. A little busier but probably closer in your $ range would be Toulouse, a good, if somewhat Americanized, French bistro. They have a nice patio, and unless it rains, the weather should be great.
I see that you are from DC and have read a few posts on the Asian offerings there, which are limited. Garland and Richardson both house a large Asian population and have a variety of varied cuisines from Chinese (several regions) to Vietnamese (majority of South but some have a combo menu of North and South), Indian, Thai, and Japanese. If you would like some other recommendations for this area let us know.
The places in and around North Park will not be considered hole-in-the-wall, nor will a hole-in-the-wall feel nice and somewhat formal. We do have some dodgy hole-in-the-walls with some great food but they will not be the somewhat formal place you might be looking for. The recommendation below is formal for a Vietnamese place (in other words it is not smokey, have Vietnamese sopa operas, karoke, or kung fu on - they do have a very nice Vietnamese tourism video playing...no sound though, and will have a lot of families). The place is sleek in the decor but you won't find that cuisine anywhere around North Park.
It is a fairly new place, a modern look and crowded on the weekends. Last time I went with friends it was about $15 per person but we had four dishes between us. The first was oven baked Catfish which was excellent served with rice paper/ w hot water, lettuce, an array of herbs, bean sprouts and dipping sauce. A medium fish would feed 3 people generously and makes for a great conversational meal $28.95. If that is not to your liking a Lau Thai Lan, a Thai style hotpot with mixed seafood (can specify what seafood you like or don't), water spinach and vegetable in a spicy broth. I heard it was very good and it is $26.95 served in the traditional hot pot way and cooked on a burner at your table. This also comes with a generous helping of bean sprouts, herbs, noodles, etc. For some interesting small plates or appetizers I would recommend Nem Nuong Cuon or grilled pork patty spring roll (2) $2.95, Chao Tom or grilled shrimp ball (2) $4.95, Bo Tai Chanh or small bubes of beef marinated in a lime sauce $12.95. That should get you started. It would be a stark difference from the food typical to the neighborhood around North Park...it will be cheaper, the food lighter, and healthier.
Saigon Block - (Just off the NWC behind the McDonalds)
2150 E. Arapaho Rd
Richardson, TX 75081
Given your price range within the radius you're looking at, plus wanting something comfortable, yet a bit elegant -
I'd suggest Patrizios - Highland Park Village.
There are also a number of upscale (wood-burning oven) pizza places that you may want to consider.
The Northpark area is about the highest dollar area you could be in, so to hit your budget and ambiance requirements for the dinner menu is a bit limiting. I'm sure others will come up with something though.
I'm staying by Northpark mall but have a rental car so anywhere within half an hour is fair game. I'm looking for a nice place to take mom and new boyfriend- so something that feels nice and somewhat formal but its on me so not too expensive. the only "not" would be mexican, since thats the rehearsal lunch earlier in the day. I appreciate any suggestions you all have.