new problems on my new car

[SHISVX]

i am not only computer stupid, but pretty car stupid. i fell in love with this svx and had to buy it. at first everything was perfect. now-the speedo don't-which is to be fixed soon, my driverside door will not unlock-even with the key-they tried to lubicate it(worked for a while and it just stopped again), some jerk desided that it would be a fun idea to rip my antena out-if i can't figure out how to fix it-i'll just cut it off-my check engine light comes on here and there-maybe an O2 sensor? i love this car and i want to keep it for a while. so if anyone can help, i would really appreshiate it.