You have a 64 bit video card, at the low end for the sim. To be honest I don't think your going to see that much (if any) difference between the two. They are that close together where only a close examination, not a moving "target" would need one over the other. Yes Tri is the one to use but with your specs that's the least of your problems.
I hope I'm not being too harsh.
By the way only use anti-aliasing in the control panel of the card, don't have it checked in the settings of the sim
I thought you'd like to read about both.
trilinear texture filtering
Like its less sophisticated cousin, bilinear texture filtering, trilinear filtering is a complex technique used by 3D graphics cards to make movement through rendered landscapes realistic even in fast-moving games.
bilinear texture filtering
Bilinear texture filtering enhances a computer's ability to scale 3D graphics in a smoother, more realistic way. With 3D graphics, especially with games, you don't want a graphics card to grab texture maps from memory and simply write them on your computer screen: as the polygons drawn onscreen grew bigger, they would take on a blocky look. To improve the ability to scale 3D graphics, you need to filter them. Bilinear texture filtering does this by averaging the four adjacent texels (the basic elements of a texture map), thus creating a new texel that renders a more subtle, realistic texture.