Are you going to have car? I ask becuase the convention center is pretty far from WDW. The shuttle times from these hotels, if offered to WDW at all, are limited at best. The convention center area as you may have guessed is mostly high end business hotels without the resort feel. I've stayed at The Peabody (right next door) it's a very upscale nice hotel but I'm guessing over $200 a night. Also add in parking fees.
On Universal (street, road, parkway, highway whatever it is I forget) is several mid scale hotels/motels. This backs up to the convention center and is walkable but is not right next door. Do keep in mind that the orlando convention center is huge, as in several city blocks big, with lots of buildings. We have stayed at The LaQuinta and Hyatt Place on this street both are nice, clean, affordable options but again not resorts. Parking was included at LaQuinta. I don't recall about The Hyatt Place. Both have a free self serve breakfast. The Hyatt was the closer and nicer of the two but I would stay at eiter again.
When my husband has a convention I often just stay on site or at The Caribe Royale if allowed and drive him over to the convention center in the morning and pick up in the evenings. The Caribe is a few miles away from the Convention Center but to me has the most resort feel of the convention hotels . Waterfall pool, pool slide, and pool side bar and grill. Depending on the convention they might offer shuttle service to the convention center. Rooms are almost always under $200 a night here. Heck, if I'm spending my cash I look for deals and the most I have ever paid out of my pocket is $129 a night here when we our paying for the room. We often stay here rather then a value resort when we go to WDW for fun.
Lastly, there are convention centers at Caribe Royale, Gaylord Palms and Disney's CS and a few other hotels in the area. Are you certian it's at The Orlando Convention Center and not at a convention center in a resort?