Shalom, I'd say to get a G36E Valkyrie, G36KE, M6A2 SRT, or M4 Super 90.
G36E Valkyrie and G36KE have great accuracy (especially with a modded scope)
and their damage is just gruesome for your target.
M6A2 SRT, judge it yourself, i've heard it's beast, I never had any hands on play with it though.
M4 Super 90, it's basically the cheapest gun in Combat Arms (skillfull wise)
It's Damage, RoF, and range is amazing, and because it's a shotgun, you can shoot and reload as you go. Although you may get rage kicked, it's still worth it ey?
You should also stock up on some GP / XP Passes, about 2 40% GP and XP passes.
as well as up to 2 Black Hi-Sec Keys, 2 Renewal Kits, or 2 GP Cases.
Live Long and prosper, good luck.
Sorry about your grandmother Mouzie.