SFF PC ... wireless card "future expandability" question?

Approximate Purchase Date: I've already bought everything EXCEPT the monitor

Budget Range: (700 or so)

System Usage from Most to Least Important: word processing, surfing the net, iTunes / Netflix / Youtube, basic audio/video encoding, simple "flash-based" games on internet

Are you buying a monitor: Yes

Do you need to buy OS: No

Preferred Website for Parts: Newegg.com

Location: Portland, Oregon, USA

Parts Preferences: Intel "Ivy Bridge" compatible

Overclocking: No

SLI or Crossfire: No

Your Monitor Resolution: Plan on 1920x1080

Additional Comments: A trusted friend helps me build PCs, so my knowledg is limited somewhat, though I can pick components decently (I think). This computer is for a 12-year-old girl who does her "gaming" on PS3 ... I might have gone "overkill" with the CPU, but I just couldn't pull the trigger on the i3-2100, and her birthday is BEFORE the Ivy Bridge i3's come out (early September). I'm skipping the SSD, and just going to put the OS on the 1TB HHD (partitioned).


Here's what I have:

CASE/PSU:
SILVERSTONE Sugo Series SG05BB Mini-ITX Desktop Computer Case with SFX 450W 80+ Bronze Certified / Single +12V rail Power Supply

CPU:
Intel Core i5-3450S Ivy Bridge 2.8GHz (3.5GHz Turbo) LGA 1155 65W Quad-Core Desktop Processor (Intel HD Graphics 2500)

MOBO:
ASRock H77M-ITX LGA 1155 Intel H77 HDMI SATA 6Gb/s USB 3.0 Mini ITX Intel Motherboard

RAM:
CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CML8GX3M2A1600C9W

HDD:
Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

OS:
Microsoft Windows 7 Home Premium SP1 64-bit - OEM

OPTICAL DRIVE:
LITE-ON 8X Slim Internal DVD Burner 8X DVD+R 8X DVD+RW 6X DVD+R DL 8X DVD-R 6X DVD-RW 8X DVD-ROM 24X CD-R 24X CD-RW 24X CD-ROM SATA Model DS-8A8SH - OEM

MONITOR I'VE BEEN CONSIDERING:
ASUS VS Series VS247H-P Black 23.6" 2ms LED Backlight Widescreen LCD Monitor 300 cd/m2 50000000:1 (ASCR)
She wants a 24-inch, and she may eventully connect her PS3 to it. I don't need a monitor with built-in speakers, because she has THESE:

SPEAKERS:
Logitech Z520 26 Watts RMS 2.0 Speaker System


NOW ... HERE'S THE MAIN QUESTION:

She lives with her mother (about 5 miles down the road) and they currently do not have internet access ... they will get it with the addition of this PC. I have no idea on whether they will get something that allows the PC to be "hardwired" for internet (my preference) or whether this PC will have to be wireless.

On that note, I plan on installing a Wireless PCI card or whatever, similar to THIS one that I have in my own computer:

D-Link DWA-552 Xtreme Desktop Adapter IEEE 802.11g, IEEE802.11n Draft 2.0 32-bit PCI Up to 300Mbps Wireless Data Rates Wi-Fi Protected Access (WPA, WPA2)

From what I can tell, the MOBO I have only has ONE slot for PCI stuff ... if my daughter ever decides that the Intel IGP is "not enough" for her needs (ie, two years from now) and I want to install a graphics card, like this one:

XFX FX-775A-ZNP4 Radeon HD 7750 Core Edition 1GB 128-bit GDDR5 PCI Express 3.0 x16 HDCP Ready Video Card

... am I then "screwed" because there's no place to put the video card?

Should I just leave that slot open, and get her a "USB-based wireless device" ... or just worry about that IF the time ever comes?

I'm sure that the IGP will be plenty for her, just like the i3-2100 would have probably been "plenty" for her, also ... but ...

... anyway, any input or advice is appreciated (other than my daughter is a spoiled kid - that I know   ).