Rather than just trying to give you general advice without seeing the car seat, where I live the local fire department will check your car seat for compliance to safety codes and if you bring it to the firestation I believe they'll basically help set it up properly. It might be worth checking in your area.
General guidelines are that an infant has to be rear facing, backseat only. Modern seats and cars come with a belt with universal clips at each end. This belt passes through the car seat and clips into the universal connectors which are hidden either between the seat and the backrest in the car or are accessible through slits in the backrest. The belt should be secured tightly enough so that it doesn't move a lot while a little side-to-side movement is ok.
If you don't have the universal connector belt the seat can also be secured with the cars seatbelts. Check the manual for your car for diagrams showing how this can be done.
The seat should also be tilted back (towards the front of the car). Some seats have level indicators built in which tell you if the seat is tilted within the proper range.
There have been some recalls of Eddie Bauer car seats and the list of model numbers might be worth checking (if you are able to determine your model number without the manual).